try moving your harness lines back? if u shorten them too, you'll either ctapult or fly downwind like a rocket! add some mast foot pressure and i don't think u'll round upwind anymore.... don't get scared, lock in , work those abs and unlock ur shoulders! thats my 2 cents, but i might be wrong! with those knots and a 7m, u should be flyng! p.s. i have my mast foot back 80% of the way in the same conditions, not forward, so i hit the chop with the rear part of the board.
once you get the trim right, u turn up and downwind by curling your toes or flattening the board with your feet.