Get, yes with the added tire rubbing info, I would say it is weak springs and rubbing top of sway bar link.,I would get new springs and not risers...
Because then you will just have old springs .....with risers!
If you can do springs yourself with a quality spring compressor, not a place for cheap tools, they are relatively inexpensive. MOOG springs from the local auto parts or one of the great Pontiac houses, Performance Years, NPD, Ames etc, even year one or Jegs or summit all supply those.
If you want a shop to do it price it out, with these classics you might even buy the springs and don't forget the rubber on top of rear springs and put them in the trunk and see if a local shop will install them at a good deal.
If bushings are original, good time to have that done as well.
Spacers will not help your ride quality and the old springs will continue to sag, old age, things sag. But springs are a very important part as you know and really are the absorbers of shock, while the shocks just stops the springs from oscillating! So not only a better ride height but better ride and handling with new springs.
Sounds like you did some great front end work, but alas one thing affects the other