I had the same card as you with 16 MB and never ran out of memory. Sure if you dearchive to ram: a lot then you can even fill 128 mb but seriously how often are you going to do that as opposed to dearchiving to hard drive?
No game will ever need more than 4 mb.
Save your money and buy an FPU instead. If you want to do some 3d renders you might need more ram to open some big lightwave scenes, but for that sort of stuff you are better off firing up winuae becausee it will be a lot faster to render images than the 030 is.BTW if you do get into renedrtring you will need that FPU, but I just renedr with winaue, save the anim to compact flash and transfer to the A1200 to play it back.