From what I've read, if you're running 256 LEDs, you get them where you want them now, but to change #240 requires shooting out 256 color commands. Is this your only option, or might there be another alternative to achieve your goals? You haven't really stated what you're building, just what your intended approach is. As far as the 256 Variables, if you're running into Memory shortages, you could try a newer PIC with more Memory.