Different Key Signatures/Independent time signatures
This IS playback sensetive!
It's not as simple as it looks...
No it's not! It's so damn, difficult that I have forgotten how to do it. Plus these two are completely different between them

DAMN!
Alright...
Take a look at the following example:
Example 4.1
This is the right way to go with it. No matter how complicated it looks. It will weave away all fears from any performer for a possible tpyo (typo)!
This way, it is obvious that the first staff, plays on B minor, the second on D# minor and the third on D minor... Notice that this principal does
not apply for orchestral scores, and for transposed instruments! ok? Deal?
This is a piano score! So the one performer might find that tricky!
Now, you may ask yourselfs (or me) why on earth go to such length and not write accidentals all the time? Well. Firstly because I was experimenting with Finale back then in 99, but mainly because if the whole piece goes like this the pianist will kill you with the 100s of accidentals in each stuff (plus all naturals to keep the score... healthy :p).
So. How to do it in Finale:
Bloody HELL! that's taught!
There are MANY steps to take, so I'll number them and hope you (and I along with you, form back in 99... wtf remembers what happened back then?) will understand!
1. first fo all, all 3 staffs must have checked the option for
independent key signature, which can be found in the
staff attributes on the staff tool!
2. For our purposes we use
Maestro font, 18 size. n = natural, b = flat and # = sharp!
3. Go to the
key signature tool -> (left click) -> other. Or double click on a bar, depends on the Finale version you're using. Your goal is to go to the
key signature window.
4. now for the damn tricky part! On the right side menu, where it says "major key", choose "nonstandard".
(Non relavent step, but very interesting for those with crazy ideas):
4,5. If, on the
nonstandard key signature you click on the
nonlinear key signatures and then the
key map button on the leftmost bottom edge, you will find a keyboard drawn. Blacking all the above boxes, will leave no sharp, blacking none, will leave all 12 sharps (!) Playing around may lead you to the queer key signature of A#, C# and G# (with that series). Have a blust if you will!
5. But back to what we were doing. Choosing
nonlinear key signatures and then
accidental order and ammount (2nd button from the left towards the bottom) will take you to the window where you can choose where each sharp is placed, and how many semitones up or down you want it to go. (- or +). 1 is 1 sharp, 0 is
nothing! (not natural) and -1 is a flat.
6. In order to make the key signature as the example on the first staff (2 sharps and 4 naturals, you will have to set the first two (leaving all steps untouched!) at ammount 1, then the next 4 at ammount
2 (!) and the last one at ammount 0. Attempting to put 0 at the third accidental will bypass all further changes...
7. Then go to
Attirbute (last button) -> Symbol List ID -> Insert (first button) TWICE. Then click on next and input the following values:
alter: 1
Characters: #
click on next and enter the following values
alter: 2
Characters: n
8. This should do it!
Apply the same ideas for the rest of the staves...
Poof! (I wasted around 1 hour to try and remember this

)