Same here, Roger.
I had this problem on the very beginning, solved it exactly this way and then forgot about it completely until I got on the way smaller and narrower board.
I remember originally I solved it by reading instruction in the book to move the mast upwind until I could see the nose through the sail and _then_ sheet in.
BTW: exactly after 1.5 year after I got on the windsurfing board for the 1st time I had a full-control session last weekend on my F-type and 10.0 Gaastra GTX in both straps, planing from underpowered to slightly overpowered, lifting the windward rail and bearing off in the lulls (I was able to stay on plane in really low wind) and getting really good upwind angles in the gusts (going 1 mile in one direction). Got used to the speed enough that I tried planing jibes a couple of times (not successful, but not too bad either). Completed a couple of helicopters on this jumbo sail ;-).
Thanks to Roger and other people on this forum.