The simple solution to that is don't use BT; they *are* bastards.
Patches ... hmmm. Depends on what data you actually changed. Text data is tiny. I made a patch to test out Cosmo 0.75 that renamed Sephiroth. Now, that involved changing the text in about 1/3 of all the locations. (Not much was changed, but it did change a lot of files). The patch was <200Kb. Text compresses well.
Graphics, OTOH, aren't tiny, and the FF7 formats aren't compressed - though you could distribute them in JPG format or something, then write a program to convert em back into FF7 TEX's.
Music, if you used MIDI's, also tiny. Soundfonts would be the biggest element, but they should be optional anyway - not everyone has an AWE/Live.
Sound effects ... we wouldn't need many new ones.
Basically, a patch isn't necessarily going to be large, *especially* if you reuse data from the original game for lots of stuff. Which you should.
Incidentally, how do we get authorised for the private forum on this? I'm kinda hoping to be included in the discussion on this Actually, what is going to be discussed in the private forum? Just the story line, or the technical aspects too (as you might expect, technical is more in my line, though story interests me too).