I recommend a 7" wheel with the 10.50 wide tire.
I routinely air down to ~12 psi for offroad without any problems, as I still have a 3.5" difference between the wheel width and tread width.
With an 8" wheel, you only have a 2.5" difference. This can cause you to lose the bead seat or pack the bead with mud/gravel, making airing back up impossible without cleaning the bead. (BTDT
Here's a couple pics of 33x10.50 MTs on 15x7 wheels with 3.75 backspace and Rubi flares (stock flares in the first pic).