RE: How to know when you are overpowered?
Hi again Windsurfer,
I think you said you have your footstraps all the way back and outboard, but if you don't, you might want to try this as well.
It's knda hard for me, at 170 lbs. to relate to some of the problems you bigger guys have to deal with.
The GO 155 sounds about right for your conditions, but the GO 170 would give you a bit earlier planing, and maybe better upwind.
If you were to ask, I would have recomended the GO 170 for a fellow your size. I usually suggest the GO 155 for smaller lighter sailors.
No reason you can't have a great time on this board, but it's going to require a larger rig and a bit more wind for a big guy, but on the other end of the spectrum, you should be able to sail the GO 155 in well over 20 knots with no problems so anything you'velost with the smaller GO 155 will be more than made up in a higher wind range on the top end.
Hope this helps,