Keystone Klassic's????

Had Keystone Klassics on my black 73 Dart Sport. Loved them so much I plan on using them on the one I'm restoring now. Only issue is, in 15" size, they do not come in the backspacing needed to get a wider wheel. Per the manufacturer, I'll have to order a custom backspace to get what I want. Don't know the cost but I'm sure it will be up there.