Well, back to the OP. It's going to be pretty tough to keep a truck with a GM D60 and 16" wide tires at the 80" width. The axle is 69" WMS to WMS which means the edge of the tires can only stick out about 5.5" on both sides from the WMS.
On paper an H1 wheel with the stock 7" backspacing along with 16" wide tires would put you right at 80" overall width. Since the H1 wheels are 16.5" that doesn't help you so I won't even bother going into the issue of trying to make that setup work in regards to clearance issues. It looks like even a factory 2500HD wheel that is only about 6.5" wide with 5" BS would still put you over width on paper.
Doesn't sound like those tires are that great of a deal compared to the hassle of trying to make them work.