A bit of high speed video would be great here Geoff. As I see it the arrow floats in mid air quite soon after launch. A bit of + nock hight gives the arrow chance to clear the rest. It seems most compound archers favour a rest with just enough tension to hold the arrow up at full draw. I set mine to sag when the arrow is half way down the draw. I'm not keen on drop away rests as it's just something else to break down just when you don't want em to.