Single stage paint should give you a nice glossy finish especially after you buff it out. Adding clear to the mix will give you more depth to the paint, but will also complicate the repair process if you happen to need it.
If you want more gloss and depth, you should use a color/clear coat process.
Don't know advertised gloss? I went to the paint house and said I wanted a single stage for 1966 lt blue.
Is it possible that you told your paint guy you wanted paint for your interior and he gave you a lower gloss, so it didn’t reflect the sun? This is typical for interiors.
