You got a nice and sure touch there Capt Soup.
It's going to be fantastic when it's dolled up and trimmed out.
Epoxy primers will seal the wood, making finish painting easy.
Primed with thin white epoxy and with SW Proline sanding epoxy primer for the cosmetics.
Seal all wood surfaces in inaccessable areas to keep mold at bay, but aye didn't bother with finish coat.
It would be better to have easy to keep clean epoxy enamel there, to make sure it sticks forever. Too much for me.
ShermanWilliams makes great paints, including hard to find marine paints.
Used their Proline sanding epoxy primer all over the boat. BUT
But I don't/can't do that anymore.
Now go with waterborne, water reducible coatings.
Inside painting you might find low VOC SYSTEM3 waterborne sandable epoxy primer useful and even FUN.
WR-155 (Water Reducible). It can be used as a general epoxy primer.
But it's meant to be the prep for their WR LPU paint which you'd use outside, enjoying the benefit of no toxic flamable solvents and fumes. You don't need a first primer with the 155 - roll it on and sand it - for any paint.
There's a learning curve (and a wallet curve) with System3 stuff........ but for me it's been worth it.
Before any paint (last concession to the toxic gods) just naturally will brush on a slightly thinned (penetrating*) coat of laminating epoxy to actually seal and waterproof the plywood. Keep paint from peeling. Easy and quick. Do work with the least toxic laminating epoxy availablle. Don't think they've waterborned that stuff yet!
Not mixed with anything and put on thin, its easy to sand/scuff/smooth and follow with any fairing mix and epoxy sanding primer. Or nowadays skip the primer with the new bigbox acrylic/latex paints. Haven't done that. Depends on what you want to end up with. Or maybe how patient you are!
Shy away from urethane finish coats because imco you can't really successfuly paint over them down the line.
Also it's best to stay away from shiney anything down below, including varnish. Satin hides many sins.
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*you don't need to buy a special sealer like solventborne CPES. Mix your own using a little xylene. Bad stuff. Slap it on & leave the scene.