an "Acceptable score"

for Midwest Microfest:

Here is an example of what is "aceptable":
http://works.music.columbia.edu/~chris/17tet/17waltz.pdf

PDF.

Two pianos, preferably on top of each other, so players can cue off of each other and see what's going on.

No wierd notation. Just straight piano notation.

Pianos (to the side of the staves, where the instrument name goes) should be labeled either "C D E F . ." etc. or "C# D# E# . . ." or whatever the two scales are.

Incidentally, since the scale that a given piano is playing doesn't change through the piece, you can use sharps or flats or whatever is easiest for the pianist to read.