For me it's like this: (PS3 controller)
Zoom in/out - L/R3 (click in stick) (also used for caveman)
Lower/raise - L/R1 (shoulder bumpers) (also used for revert/spine/spin)
L/R2, triggers, unassigned.
I think triggers might still have the issue of being treated as the same buttons (if you hit left trigger, it acts as if you are hitting right trigger as well) I am not sure about this though.
I don't think I can help you with this, but I wish you best of luck!
Sup, I'm Chatter. (HN.Chatter) my Skype is thedudecalledjoris.
My clan is HN. Henchness!
I'm always LF people to play with, also wanna join a clan some day and do wars/competitions and stuff.