I "purchased" 33x12.5x15's, im getting them installed on Monday. The tires i have on my jeep now (in the picture above) are 31x10.5's.
My wheels are 15"x 8.5" (I think) and have a descent offset, my 10.5's stick out about 2-2.5" from my fenders as it is. The 12.5" tires actually are measured at 12.8" so I'll have a pretty good stance.
Typically, depending on the tires and if your rims are bent up, it could take a lot of weight to balance off road tires. My wheels are in good shape, and the tires are Nokian, a good quality tire. They should balance out good.
If you are thinking about doing this in the future make sure that the tire shop that balances your tires use hammer on weights vs. the stick on weights, stick on's are for mall crawlers, and the french. Hahahaj, plus they will fall off eventually, once you put the pressure washer to um.
I had and alignment done not too long ago (self done) and it is dead nuts, about 1/8" in on my toe maybe a tad less. Wheel is straight and it tracks straight. So that being said, I should be good once my new tires are installed but if i do need and alignment i will do it myself at home. Chances are the toe in and out will be the same.