I have 4 of my custom made tones assigned to footswitches 5, 6, 7 and 8.

I was wondering can I assign 4 more to Footswitches 1, 2, 3, and 4? Or are those simply for turning effects on and off?

Also when I go to options, it says FS mode: A B C D or FS-8....whats the differnece?