I was asking because I was wondering how much mobility you had. Based on what you said, I'd stay away from a cat unless you have some big $ to buy/maintain a large cat. If so, go for it... the large ones are roomy in the cockpit. I don't think you'll find the smaller cats much fun to get in and out of w/o a crane... and I'm not joking about that. Even having full mobility, I have a hard time getting in/out of most cats.
So how much use do you have with your arms? Limited to the point were you'd require arm rests with some upper arm restraints, or can you support your arms enough to control the boat in offshore conditions w/o support?
I'm just trying to figure out what needs to be done for you to accomplish your goals.