Well, now you've got a mostly official notice that 350 is accepted widely across canada.
As for the Semi/Full debate? Just have two different slots of game time, one with full auto, one without. Alternate the slots. I know that I rarely use full auto. Hell, I've got an AEG that only shoots semi and I'm fine with it. This way people who are playing full auto and want a "break" can hop into the semi slot, while people in the semi-slot who want to give the full auto a try can hop into that.
It's fair, it's going to please the most amount of people, and you've got a standard FPS MAXIMUM (that's the key word, maximum, not all guns are going to be shooting 350, hell, they'll most likely be 320-340) to go by. Setting up semi/full games from there should be easy.
Hell, buy two packs of zip ties, one red, one yellow. The ones that meet the full auto requirement (I believe you mentioned 320) get a yellow zip tie. The ones that go over that, get a red one. Makes life easy for you.