Re:'light truck' tires for the B-body:
With a curb weight between 2 and 2.25 Tons, a towing capacity somewhere between 2.5 and 4 tons, a live rear axle (8.5" and 9.25" were available), a full frame with supsensions sytems for the bumpers, recirculating ball-and-links steering, and steering stabilizers, I think the B-body is one of the most aerodynamic trucks that I have ever seen. Besides, the Tire Rack hasn't received a single complaint from Pirelli Scorpion users.
As far as stock circumference is concerned, I know that AutoXers and drag racers have used wheel'n'tire combos that were shorter than the 27"-tall 255/50R17. I wonder if their ABS lights complain to them. Stock for the B-body is anywhere between 27" and 28"-235/70R15.
If I could afford it, though, I would appreciate 17" rims that look as close as possible to either the N97 "cop" rims, or their wider cousins, the 2WD FullSize PickUp/Suburban rallye rims.