I would recommend powdercoating it to show the "raw" steel and still get decent adhesion.
A friend did that years ago to a Ritchey mountain bike frame to show off the brass.
Just blasted & PCed clear. Very subtle urban chic anti-theft kind of look to it.
Minimal functional hi-end but "It doesn't even have a paintjob, I wouldn't steal that one" look to it.

So, what you do to the tubes before PCing is up to you. So far you have the polished lugs, how about an aroundthe tube graining done with really course ScotchBrite pads?
Then maybe a tinted clear in blue or red. (otherwise known as CANDY colors)

The other choice is paint, and paint without primer is like, welll, ...paint..without primer.
I suppose if the frame is clean and free from all rust, then just burrying it it 4 or more coats of clear might last you several seasons.

YMMV..