Here think of like this,
If you get a 11.50 wide tire and put it on a 10 inch wide wheel that leaves you a .750 bulge on the tire. Which is very little.
If you put it on an 8 inch wheel then you would have 1.75 to work with.
When selecting a rim for an offroad tire in my opinion it is much better to have a narrower rim with a wider tire, this applys more pressure to the bead due to the bulging factor, which in turn will help keep your bead seated and the tire on the rim when wheeling. It will also protect your wheels, The side of the tire will hit the side of a rock or rut before the side of the rim does, there for protecting it.
I run a 8 inch rim with a 12.5 tire and i am very happy with it, I ran a 7 inch wheel with a 13.5 tire before that had even better results.
So as long as your not planing to run a 15 inch wide tire the 8 inch wheel is the way to go.