In theory I totally agree with this. But here's the thing. You can have someone that has 20 years of alignment experience now that has never aligned something like these cars. And for liability reasons, the major tire and alignment shops won't use anything other than factory specs now, even if they have some employees that know better than just "putting the screen in the green".
I used to have a guy at one of the local major chain tire shops that raced dirt track stuff, he understood the whole factory alignment on a 40+ year old car thing and would do custom alignments and wasn't worried about my aftermarket suspension parts. But he left, and that was it for all of the major name tire and alignment shops near me as far as getting a custom alignment. So now you have to find an independent shop with an alignment rack, AND an "old guy" that knows a little about old torsion bar mopars. Realistically, most of those "old guys" are now long retired alignment shops are not somewhere you usually fine 60+ year old guys. I'm not saying they aren't out there, but going out and finding somebody like that isn't easy. And custom alignments at independent shops can get expensive real fast. You basically have to find a race shop around here, and they're aren't a ton of them with new alignment racks.
Maybe where you're at there are independent shops all over the place with experienced employees, but around here it's pretty much all big name national chains. And there's a lot of them, so, there aren't really any independent shops. 10 years ago you could talk guys into doing custom stuff at places like that, but I can tell you I haven't had any luck with that in the last few years. Which is why I bought my own alignment gear.
As far as the Skosh and getting more than +1.5° to +2° caster, it depends on your components. Yeah, with all stock stuff that's about the limit. But even with just offset UCA bushings you can get up around +3° caster. If you have tubular UCA's like it sounds like the OP does, it depends on the brand and style but usually you can get up to at least +4° and sometimes +5°. If you have adjustable UCA's like I do, you can almost get whatever you want. On my initial install I had to start dialing my caster back from +8° from where I had the generic setting on the adjusters. I run at +6.5° caster. So it's completely dependent on what parts you have.