wheel/tire question

[anviltester]

so I've been searching for a set of wheels for my project - 1969 c10 step side. It has the 71 rear axle in it so its not the shorter one. Its also bagged w/ porter built stuff and 3/4" body drop. My question is this - i have found some discontinued american racing wheels but can only get them in a 20x9.5. the price is right but will they fit and tuck under? the rockers are about 1" or so off the deck when aired out. i think the backspace is 5.75 on them and the offset is a +15. I don't mind skinny tires but just want them to fit.