Hi Raislin.
I had the same conundrum a short while back, penning out the various alternatives: 4+4, 2+6, 1+7... Unfortunately it's not quite as flexible as that regarding playfields - it's 4 + 4 I'm afraid, you can't gain extra by limiting yourself, although in theory if you go for less than 4 it should still be faster (?). So it's a maximum of 16(15) colours each. You can however have a different palette for each playfield, and then another for the sprites.
The Amiga is versatile, you can use sprites to form the second 'playfield' (16 cols) and have up to 256 cols for the foreground - 16 of those will be used for the sprites. You can also use the copper to generate a varied palette for the background, a very interesting (and to me very tricky) peice of kit for the real experts.
More bitplanes can slow down your game engine. 7 bitplanes would give you 128 colours, you might have to experiment and make some compromises to get your game up to speed.
Pending a better answer which I pray proves me wrong...
Anyway, I hope you go for it
