I don't know that anybody on the larger side could truly get in and out "comfortably" of a full race, full door bar car. I'm 52, 6ft, probably pushing 220 lbs, with non-extended, race, full bars, and right know I tend to just climb all of the way over the top of the halo. Of course mine is still on dollies, and I haven't gone back and added the quick detach steering wheel, so some of that might change.
I highly recommend finding one to climb in and out of to see how it works for you before buying. Even if it means an overnight trip to see one. I wish I had, and I would probably have ended up with an extended chassis just for the slightly more room to get in and out. There's plenty of room once in the seat.