I have quite a few here actually I think I have a 69 for sure here that could get some new perches. Make life easier in the long run and wheels would be more available too.
Yeah if you want to run a square set up on a Duster/Demon/Dart Sport without doing a bunch of bodywork the 68-70 B-body rear is just about perfect for making the wheel offset the same front and rear. And there’s a decent selection of wheels in the 18x9, 18x9.5” sizes with a +35 offset. 18x9.5’s are better with a tubular UCA in the front because of rim to UCA clearance at full steering lock and full suspension extension. With with a “V” shaped tubular UCA (vs a “U” shape) you can run 18x9.5’s or even 18x10’s up front. 10’s would be easier with some fender lip rolling though, and a 275/35/18 is still about as wide as you’re gonna go so the 18x10’s aren’t really necessary, 18x9.5’s would be great.
The funny part is when you get to 18x10’s or 18x11’s the A-body rear is better to have, because for some reason once you go past 10” wide rims the popular offset goes back to like +10-15.