I've sailed and taught in Mud Lake a couple of times, and been to the Texas City Dike at least 5 or 6 times.
The Rio L (at your 225 lbs.) should work well for you and help you to get onto a shortboard a little more
For a big guy, with some skills, you will need a fairly large sail.
Most sailors are using 1-2 meters larger than what you used 20 years ago.
The masts and booms are quite a bit lighter as well.