buzz88,
On my 87 BII, I am currently planning to mount 235/75r15 Cooper Discoverer A/T's on 15" x 8" black steelies (pulled from a late 80's Jeep) to dodge the cost of regearing for the next few years. If you have 3:73's, that is the perfect tire size.
I like the idea of using stock Explorer wheels, the set you have look nice; pretty sure they can handle 30x9.5's, though 15x8's are hard to knock! I used 15x8's when I 1st went to 30.5x9.5 without fender trimming, no lift, only the slightest rub on the outside with steering cranked to the stop.