256 byte page boundary prob.

Is it good practice to keep all small lookup tables located at the top of page 0, before the start of the main prg?

It is the place most people put tables to avoid page boundary problems but it is not the ideal place. Due to the reset and interrupt vectors being there you lose a few bytes (typically 12 as you shouldn't have just a goto at location 4). On a smaller chip it makes more sense to use the last page and just load PCLATH with it's high address.

Mike.