I'm also a hand pronate or superinator, not a throat spinner. I like to keep my racket at a constant angle, about 60 degrees from facing down at the ground...or is that closer to 30 degrees? SW grip forehand, 1hbh backhand.
The pronation needed to switch from ready forehand to topspin backhand is a natural preloading of the arm to hit topspin backhands for me.
Conti grip for fast serves or tentative mind (mine).