Guy Cribb says to keep the hips parallel to the sail on all points of sailing even though it's not that comfortable. It allows you to pull the sail in more easily.
I don't know if what I did is correct but I often have trouble feeling comfortable going upwind and last sail I bent the front leg a lot and held the boom up near the mast. I pulled by sticking my bum out against the sail into the seat harness // with the sail with my body slung forward..I felt like I was in the groove for once!
The junction in between my lower ribes was sore after and the inside top of my legs ( I could hardly pick my foot up to change gears) but it worked!