You definitely want a 33" tall tire, and nothing too skinny, right?
I'd say the SX's are out, because with you're light weight, the 15.5" wide tire will float all over the place and not grab, seen it many times in the terrain we run. Most notably a guy running a 304/auto/Scout D44's on a YJ, he couldn't get up the easiest slope because he was just scuffing up the surface. He's since gone to 35x12.5 Claws and loves them.
Too bad Interco isn't still making the 34x10.5, that'd be the perfect size.
I'd have to stick with the 33x12.5 bias then, but I'd look into the SSR's a little more, I know a lot of people had problems with weak sidewalls when they were first introduced, but I have heard they've strengthened them. The 6 ply (I think orginally they were 4 ply) would be a lot more forgiving than the 8 ply of the bias with your light jeep.
Give the guys at East Coast Rover a shout and ask them, they switched from bias to SSR over the last year and love them, but being so far away I don't run with them anymore. They can be found at http://www.eastcoastrover.com/
. Ian and Chris are OK, Mike can be kind of snotty, must be a Rover thing I don't understand.
Winter Harbor, Maine
'81 CJ-8 Scrambled, It's a Jeep, Chevy, IHC kinda thing!
'88.5 Zuki, 7" Lift, Locked, Swamped, Rolled, and just generally broken in right!