First, getting fined for that windsurfing experience is a horrendous ethical legal practice in my experience. How many will never report a dangerous situation out of fear of being convicted and sent to jail or getting a fine.

Secondly, there is a thing called horses for courses. If you plan an experience like what you describe a wetsuit is perhaps the best. If you plan to sail along land in non-survival conditions on a cat, like I most often do, the wools and fibers goes on under the drysuit.