Its not the weight...
As a 6' 6" person at 215lbs I can say the 2 issues most important to you .
A window in the sail so you see stuff. Sailed mine once without the window, put a window in before I did that again.
You have to be able to flex your body forward and do a squat turn thing fairly quickly at times. So you have to be realistic on your flexiblity.
You have other options if you have time on your side.
In my area, southern NJ, you can find a various boats like the 14' capri to the Hunter 170 in the $1200 to $500 range depending on how much work they may need. You need to be aware of what you need in for titles or registrations for you state for that type of boat. If you are less caring a boat without a title can be found at lower cost.
FWIW, I picked up all of my Sunfish for less then $300 and two of them were just because I got lucky and found the real cheap boat before everyone else and was first person to ask.
I have a Hunter 170 and the plastic hull is a problem. They can be found cheap and if the cracks arent bad are not hard to fix. It has a roller furler jib and a high boom making it a comfortable boat for a tall person.
Anyway, some thoughts outside the box.