Question 1: If you want to draw to the buffer, put a Fix 5 at the beginning of your program and a Fix 4 at the end
Question 2: Is the game over 8192 bytes? Nostub executables have to be under 8192 bytes, while MOS and DCS programs can have up to 8811 bytes of code and unlimited data. However, be warned that Axe doesn't guarantee that a MOS/DCS program will have all the data at the end. The safest way to get past the code limit once you're at 8811 is by compiling to an application which gives you 16384 bytes to work with.