Rim Suggestions for my 69 dart swinger

I have several steel rims . all are 15"x7"with a 4"backspace . 4-4 1/2" backspace is about all you can do unless you move the springs in . Steel rims are stupid heavy . My Weld Wheels are 1/2 the weight of steel . As was said , 4" bolt is hard to get rims for .