My experience with clear coat is a mixed bag. Especially on the faux tina paint jobs, and I've done a few, it can sometimes end up being 'too shiny' . The satin clear still has a sheen to it when it is applied. Also, if you do decide to clear it, make sure you get the one that is compatible with your paint. Some guys have also used different oils and varnishes and stains to 'seal' their paint jobs and give it a more 'finished' ( pun intended) / realistic look.
I've also used car wax on an original patina job to kind of give it that 'vintage fresh' look. If you don't polish it out to much, it sort of retains the aged look, without making it too shiny.
Here's a couple examples to show what I mean:
'77 Sting ray faded paint how I found it, and then cleaned it with white vinegar and water, and put new decals on, then car wax over the top.
My Mesa Buggie build, old rusty frame to start, white vinegar treatment to take off the real crusty stuff, then Zinsser spar varnish to seal the original patina.
Frame the way I got it, and I faux-tina-ed a gloss black fork to get close to the old patina frame:
Frame and fork with Zinsser's spar varnish (clear, the amber works too) on finished build:
If you are looking for achieving a heavier fauxtina look, there are ways to get that too. Let me know if you have questions or want some hints on various methods.
This forum is all about exchange of ideas and input. After six years here building bikes, I've learned so much from others!