Stance width, angles, forward lean and strap positions are all personal preference...something ideal for me...will suck for another. You can start with those binding angles, no forward lean and reference stance width and see how you feel. If you find you are too upright...maybe widen out the stance a bit. If you feel you need more response, add some to the forward lean. Its all experimentation. In regards to highback rotation, should be parallel with the edge of your board...however, some dont even bother with this. The biggest thing is to have the targas setup to properly hung your boot...this is another issue...as you have purchased one of the most customizable bindings out there..
I currently purchased a pair myself from my LBS and needed the store guys to help me dial them in. I have never seen so many adjustments on a binding before...lol