74 duster rim and tire upgrade

Hi guys, I have a 74 gold duster with a slant 6(stock suspension.) It is about due for tires and I was thinking about getting new rims so I could run 15" tires and open up my options. It has the sbp so rim options are few but I was looking at the cragar ss. I wanted to get your guy's advice on rim dimensions and tire size. I was thinking for the front going 15 X 7 bs = 4 1/8 and 15 X 8 bs =4 1/4 in the rear will these rims be a good fit and what would be good sizes for the tires? I'm looking to get a little bit more aggressive look and fill up the wheel wells. Thanks in advance!