HELP disc brake swapping

Check and see where the adjusters are now.
To have forward (neg) caster, the forward adjuster will be in a long ways and the aft will be out. With what he described the other side would be the opposite.
When I rebuilt mine, I started with all 4 adjusters in the middle, then pushed the upper ball joint to the rear a bit and used a level to be sure the wheels were 90deg to the ground before I took it to the alignment rack.
got in the ballpark doin that.
If there hasn't been any damage to the car he should be able to get it in spec without the offset bushings.
There is quite a lot of room to move those adjusters but some times need to jack up the car using the LCA, that'll take some pressure off the upper enough to move the adjusters. If the guy isn't familiar with old Mopars he might not know that.

I'd take a look at the LCA bush tho, if it's bad it'l let the lca move out (top of wheel leans in) and you might not get all the camber you need, that will affect how much caster you can get too.

Had a friend years ago take his Road runner to a frame shop to pull the frame to get more camber.
The next guy he took it to found the LCA was bad (hence neg camber) --replaced that and now frame was slightly out of place the other direction.