i use my mouse wheel and middle mouse button on my R.A.T 9 mouse thats 3 extra buttons that you can use add in the two thumb buttons thats 5 hotkeys. do you really need your camera zoom bound to your mouse wheel you throw in a shift modifier thats 10 hotkeys within easy access with one hand as shift is hardly outta the way.
I also have Q,E,R,T and F bound to hotkeys coming from a FPS back ground using thoes keys is second nature to me.