point C is a sort of. You want your body balanced. And to be honest dhillers tend to ride over there front wheel more than you think. Think of it this way. Unweight the front you have no control over steering. Its a serious balance between front and back.
Clipless pedals help in really tech sections so you don't bounce up and down. They don't really help in the turn.
Start outside and turn in. Also lean your bike avoid turning only by using the handle bar. IF you notice most dhillers we REALLY whip the bike around. We will lean the bike, keep the bike loose under our bodies and drive our hips down in order to keep the wheels on the ground.
I am terrified of heights. This sport has been and is a lot of work for me at times. Iknow your trails as they are closely related to mine. Very exposed, very technical and sometimes downright scarey. You do get used to it, but also don't look
Also if you get a chance do some lift assisted riding (like whistler) it allows you to ride the same trail 20 times in one day, you really get a feel quickly for how the bike reacts under you.
http://sports.freecaster.com/Media/Files/199_large.mov
Give that a peruse too and watch them turning (not on berms) should give you a good idea.