67 barracuda fastback weather stripping

You didn't say new or used seals. I wouldn't adjust anything to old used/collapsed seals, worn door hinges, etc...
I've taken this area apart only once and that was our 1st 67 notchback a lot of years ago. I don't recall there being anything between. Screwed in metal to metal. ( OK I took this apart on my current 67 notch also and more recently. Nothing found between there either but this car was repainted in 1992 so mine aren't the first hands on ).
If you are working with new seals, There may be more adjustment that you haven't discovered.
There are bumpers ( angle pieces with rubber band like wrapped around ) that limit travel. There is also a eccentric/cam like limiter on the regulator but I think that one limits only downward travel.
The glass shouldn't roll up and burrow into the rubber, the door wouldn't open. The glass should press against the rubber. And there's several ways to adjust that too ( latch post depth is easiest ).
At some point in track and glass angle adjustment the glass will get difficult to operate/roll up and down. good luck with it.
They are new just don't seem to be a nice fit imo but thank you for the information I'll definitely take a look at that when I get time