You should always select 020+FPU as it is the most compatible and fastest out of 020-060
But very old, badly coded games will require you to select 000
Those are the only 2 choices you ever need to use.
For games, yes. For serious use, I usually use 68040 since I've copied a lot of libraries etc from my real system. It's not any slower than 68020 for me.
