I have no experience with powdercoat but first, if to paint over anything and for best adhesion should at a minimum scuff it. Don't skimp on the details around joints or lugs.

Anyways, back to experimenting 101. I'm looking at the scenario in a different way.

NOT using a rattle can but rather a higher quality touch-up spraygun. (An airbrush is too small for the task.)

I would color tint mix a clearcoat 2 part urethane and hit it. You want a faster set with an ideal hardener mix. Let it set up for say 30 minutes, scuff it and then another coat. The thing is, you probably already have a thick coat and any paint or other is going to build up more. But, by hitting it with multiple coats of clear, you'll get some depth.

(edit: Rattlecans- some are really tricky to work with and will spit vs. whatever piddly atomization they can put out. On a bike with all the tubes, there's compound surfaces plus potential overspray to close proximity tubes. If anything, have a dust shield ready (8 x 11 in. piece of cardboard), a better brand name paint with improved plastic nozzle and use a handle grip attachment. I'm sure others can pipe in but regardless, IMHO I wouldn't go this route.)