I am a novice rider (just picked up a board last year). I have been reading a few magazines and I have noticed most professionals ride with a negative set backfoot. -9 for example. What, if any, is the benefit of a negative backfoot angle? and does negatvie mean the backfoot binding is turned inward?
I'm new myself but from what I've learned a Negative position on your back foot means your foot will be pointing towards the rear. A positive front foot and a negative back foot is what they call a "duck" stance. I'll be trying that stance out for the first time this Thursday myself.
"duck" stance, (both feet pointing away) is best for park/pipe riding. This way, riding switch your stance can be very similiar or identical if you want it in both directions. If you are just starting, Duck can be a bit hard on the legs. I'd recommend using 15 (front foot) and 0 back. That is by far the most common stance to learn with.