Mount the switch to the steering wheel, mount it to a foot switch, control it with a WOT contact, there are plenty of options that don't require taking your hand off the wheel if you choose not to.

I drive with one hand, the other on the shifter with two thumb-operated contact switches - and that's in a two wheel drive truck. Somehow, given the work that's already gone into the truck, I think you'll figure out a way to manage.

 

With my STS dual boost switch I could never get it to go from low boost to high with-out lifting the throttle. I'm not sure why, but it wouldn't...

 

Good to know, I will let you know how it turn out.