Oops. Error in my math, Overall wheel width would be 11" as noted, and 1/2 that is 5 1/2" not 6 as I typed. Sheesh. 5 1/2" minus 1 1/2" would give you 4" backspacing.
Stupid beer.
Try to find somebody local to you who would loan you a wheel and tire. I have a 33 12.50 BFG AT on an 8" rim just on the side of the house and I bet somebody near you has a "loaner" as well!