Here in the mountains it's not unusual to find a big lorry taking almost the full width of our narrow roads. Practice taking the corners nice and smoothly - not in a series of wiggly turns. If you slam on full brakes you'll lock the wheels and be quickly down on the roadway. So whilst it may be ideal not to brake in the turns, in reality you will have to do this, so practice it. Get you head up, and look well ahead - right round the turn if possible.
Frictional forces are insignificant.
This leads to the fact that heavy people naturally descend faster than light people. If you don't believe this, then take your car to the same slope and see what speed it descends without using the engine power. We're dealing with a steady descent where your weight down the slope is balanced by the aerodynamic drag, which is completely different. In a race, we therefore concentrate on reducing the aerodynamic drag. This means having the pedals fore and aft, feet pointing into the wind, knees in, hands on the drops to lower the upper body, elbows in.