70 Dart. Looking for More Castor, QA1 arms or Moog bushings?

You won't get much more than +3* of caster with the offset bushings, I certainly wouldn't count on getting more than that. Depending on the ride height, you might not be able to get that much.

+3* is not "an awful lot" of caster. Most modern cars run between +6* and +8* of caster. Yes, how much you want is dependent on the suspension design, so that's not strictly an apples-to-apples comparison. But +3* still isn't a lot for the A-body suspension.

I've run everything from about +3* up to +8* of caster on my Duster, starting by using stock UCA's with offset bushings and now running SPC UCA's from Bergman AutoCraft. I'm currently running +6.5* of caster. There is a "jacking" effect, but the additional positive caster also increases the negative camber on turn in (which is where that jacking effect comes from). It's a bit of a balancing act, and it does depend on driving style and preference too, in addition to how the rest of the car is set up. Peter obviously likes to run less, and I'm sure he has a great reason for it because I know he can get more caster if he wanted it. I personally like where my car is at with +6.5*, but I also wouldn't say that's the right answer for everyone.

For a street car with decent tires I think +3* is the least that I would want to go. That's just me. And that would be pretty much the limit of the stock UCA's and offset bushings.