You can fit 33x12.5, but I would recommend 33x10.5 (found on a lot of jeeps).

You may rub at all lock. I know my 31x10.5 will rub when turned right and reversing. Only reverse and while turned right - kinda strange.

 

I would have to completely disagree for the reasons listed in my previous post. Width and height both play an equal roll in the geometry of fitting larger tires. For every inch that you go taller, the tires will move 1/2" towards the frame at whatever angle the wheel is turned to. And for every inch that you go wider, the tires will move 1/2" closer to the frame width wise. I made this to scale to demonstrate:
Tires.jpg

As you can see, they are both the same width, but the taller one is into the frame and the shorter one clears just fine.

Exactly. "Advertised" tire size may be far from the truth. I've also seen 31's that measured almost 32" so it can go both ways.

And honestly, to get to the point, a 3" body lift will be perfect for almost any 33" tire. The wider you go the more you'll want to look into wheel spacers or new rims with the correct backspacing.