RE: Question about board
Yes, with the right equipment, and some lessons to get you started, I'm sure you can windsurf (drive a windsurfing board and rig).
Since you are big, and fit, one of the toughest thigs for you to learn about windsurfing is going to be to use balance rather than your superior physical strength.
While there is a small amount of strength required to windsurf (most of this "requirement" can be alleviated by matching lightweight gear to lightweight, less strong entry level sailors.
If you want to "teach yourself" it's going to be somewhat an uphill battle until you get all the basics mastered.
Look for a school near you, or travel to a windsurfing "destination" that has a school/training program.
Try to sail on a Start Large at first with a 5.5-6.5 m2 rig and you should be able to balance on the wide Start board nicely.
When you have your balance on the board, and can uphaul, get into the sailing position, balance your rig on the mast foot, rotate your upper body to sheet in and get underway, tack up through the eye of the wind and jibe with the wind coming across the tail of the board, you will be ready to get a Start board and a rig of 2 of your own.
Hope this helps,