Hi pa340dart,
A single stage paint can be either a solid color or metallic. If it is a solid color you can cut and buff out any imperfections such a dust or dirt in the final finish. You can't do this with a metallic color because you will disturb the metallic flakes and you will change the appearance of the area you sanded or buffed to remove the dust or dirt.
I don't remember plum crazy as a metallic back in 1970 but, perhaps someone else who has worked with that color will chime in.
If it is a true metallic you would want to use a base/clear coat system. If you get some trash in the base color coat you can sand it out and reapply some base color. Then you apply several coats of clear. If you have trash in it you can cut and buff and not disturb the metallic flakes below.
Eastwood does not produce paint and is simply selling someone else's paint with their label. I don't know who's paint it is but, you might be better off buying from the original source price wise. You might also check with your local auto parts stores and auto body paint suppliers to see what is available locally. Dupont and PPG are major paint suppliers and have first line and lower value lines available.