Fine Tuning an Original Floyd Rose

I'll start off by stating this is a guide for fine tuning a  Original Floyd Rose (OFR) bridge, not a generic double locking floating bridge (DLFB) tuning guide, although the ideas and concepts are alike for many Floyd Rose licensed DLFB's.
Floyd Rose is a brand name and an Original Floyd Rose is a type of bridge.
Your Ibanez branded DLFB isn't a Floyd Rose.
Ibanez' are called Edge and were once Licensed Floyd Rose, but not any more.
The original Edge DLFB was very similar to a OFR though.

This isn't a Floyd Rose set-up guide either, that's a bit out of scope at this time.

This is a guide to fine tune your OFR and by that I don't mean on how to use the bridge's fine tuners, I mean tuning it so it stays perfectly in tune no matter the abuse.
Not even Floyd Rose's guide on their website correctly lists a method of making sure the bridge stays in perfect tune at all times for some reason.
Most guides generally have 3 major steps:
1) Tune using the tuners
2) Lock the nut
3) Tune using the fine tuners
They don't speak about what the tuning should be when pulling up or down on the bridge which is, I think, the very essence of an OFR, right?
Should be bridge be in perfect tune after pulling up and letting it return to zero?
Should be bridge be in perfect tune after diving and letting it return to zero?
Well, yes, yes it should be.
The thing is, following most guides it can't be, you'll see why and what's your definition of 'perfect'?
Pefect tuning on an OFR equipped guitar is nearly impossible, I'll explain why later on.

Anyways, I recommend getting a polygraphic tuner.
We'll need to check the entire range of tuning for all strings once we'll get to the fine tuning bit, so getting a graphic representation of the current tuning is extremely handy.
I've got a Hardwire HT-6 polygraphic tuner and fwiw: I recommend it wholeheartedly.
A word of advice when using your polygraphic tuner when tuning though: don't press down on the strings to much when you're sweeping them all at once.
Pressing down too hard makes the other strings go out of tune obviously, so you won't get a correct overview of the tuning. Gently sweep them instead.

First things first:

New strings should be stretched before tuning!
This is so important it's not funny any more.
Neglect to do it and it won't stay in tune, I can guarantee you that much!
Put the new strings on and stretch the hell out of them by pulling up on the whammy bar as much as you can and then take the string with your fingers and stretch it even more.
The better you stretch, the more stable the end tuning result will be.

I see a lot of guides recommending unscrewing the fine tuners completely as a first step, this is wrong.
We'll need to be able to both fine tune up and down, so position them in the middle.
Here's how:

Screw the 6th string's fine tuner all the way in
Screw the 4th string's fine tuner all the way out
Screw the 5th string's fine tuner right in the middle
Screw all fine tuner's on the same level as the 5th string's fine tuner, using your finger as gauge.

Next, unlock the nut and remove the nut blocks and bolts for now, remembering which is which and in what position they were on.

If the OFR was at level, it probably won't be any more now, that's fine.
This happens as, after locking the nut, fine tuning increases string tension right up to the nut; the string's part behind the nut has a different tension.
Removing the nut changes the tension again so the bridge moves a bit.

Now, make sure the Floyd Rose's fine tuners are reset to their middle position.
Then, follow these steps:

A1) Pull the Floyd Rose up and carefully let it come back to it's zero position
A2) Tune to the desired tuning using the regular tuners on the headstock
A3) Pull the Floyd Rose up carefully let it come back to it's zero position
A4) Repeat step A2
(Procedure 'A')

Pulling up ensures there isn't any slack anywhere on the length of the string and it's a very important step on some set ups; don't skip it.
This of course means you can't push down on the bridge at this time!

Now it's time to check the OFR's tilt.
It should be completely at level with the body of the guitar and I don't mean give or take.
Ensure it's completely at level or you won't get it completely in tune in all situations later on.

Most probably it won't be level, so this is how you level it:
Note: you'll need to tune again (steps A1 through A4) after every single spring adjustment at this stage.
Remove the backplate leading to the OFR's springs in the back cavity of the guitar.
You'll see a claw plate holding 2 to 5 springs connected to a big block holding the bridge and the plate is connected to the guitar's body by 2 screws.
First ensure the claw plate should be at level with the body of the guitar!
(So, remember: if you've turned the screws at all, run procedure 'A' again!)
Now the claw is level and we're tuned again, good.
Have a look at the OFR's baseplate:
if it's tilted forward (towards the headstock), you'll need to tighten the crews in the back cavity.
if it's tilted backwards (away from the headstock), you'll need to loosen the crews in the back cavity.

B1) Check the baseplate's level
B2) Determine which way the screws need to be turned (if at all)
B3) Adjust the screws
B4) Tune (procedure 'A')
B5) Repeat from step B1
(Procedure 'B')

The screws should be evenly turned (as the claw needs to be parallel to the cavity) and they're pretty sensitive: a 1/32th turn on both of them can very well cause a 10 degree change in baseplate angle after steps B1 through B5 are performed.

Right, now the baseplate is level for the desired tuning, good.

Next step: locking the nut.
Maybe you've noticed locking the nut messes up the tuning, maybe you haven't, but it does.
So have a look, if locking makes the lower strings go flat and the upper ones go sharp, you'll need to compensate for that a bit by tuning the lower ones a bit flat and the upper ones a bit sharp before locking as we'll want to minimize using the fine tuners afterwards.
Remember: tune by following steps A1 through A4!

Now that the nut's locked, the fun part starts: fine tuning the bridge.

An OFR is a balancing act and not all the strings are pulling equalling hard on the bridge, right?
That's why we're going to adjust the strings in a certain way: from the "hardest pulling" string to the "softest pulling" one (I'm not really sure, in fact, that this is correct to be honest, but it works for fine tuning).
This boils down to this sequence: E/G/A/B/D/e.

So, it's quite easy as long as you follow a couple simple rules:
* Follow the string adjustment sequence
* After adjusting 1 fine tuner, check tuning again (all strings!)
* Only tune up
* If you need to tune a string down, downtune it flat so you can tune up
* Remember the string sequence, adjusting the E string will have a shit load more impact on the other strings than adjusting the e string

So, firstly: we're going to make sure it's fine tuned for the current bridge position:

C1) Check tuning (all strings!) & determine which string need to be adjusted
C2) Fine tune for that string
C3) Repeat C1-C2 as much as needed until all strings are in tune.
(Procedure 'C')

So far, so good.

D1) Pull up on the whammy bar as far as possible
D2) Fine tune (Procedure 'C')
D3) Press down on the whammy bar as much as possible
D4) Fine tune (Procedure 'C')
D5) Repeat D1->D4 as long as tuning isn't perfect when returning the bridge to zero after pulling up/pressing down
(Procedure 'D')

Procedure D can take very, very long and to be honest, you'll come to a point where the difference between what the tuning is when using the whammy bar and perfect tuning isn't perceivable by human ear any more and you'll only know it's off by looking at the tuner.

There's one thing I forgot to mention though: gravity.
It's the law, so we've got to obey it at all times and tuning our OFR isn't an exception.
The position of the guitar and even the whammy bar influences the tuning of the bridge.
Try it: check tuning the the guitar's flat on an even surface, when on a strap, on your lap, whammy loose or locked in different positions... tuning always will be 'a bit' off.
That's why you never should tune the guitar when it's laying flat, there's just too much difference with how you'd normally hold your guitar.

As a small reference: it's pretty easy to get the OFR to, after returning to zero from pulling up or down on the whammy bar, line up perfectly on the HT6 overview display.
The overview is slightly less accurate than the individual string tuning mode, and I can visually confirm it's a wee bit off in individual string tune mode, but I can't hear the difference any more.
At that point I could run procedure 'D' for some time extra, but I usually don't bother.