Benjamin Moore sells a primer/finish coat all in one that I'm told by the pros is the best. It goes on super and is supposed to be the bees knees. I used it and loved it but it's only been a couple of months so I can't tell you about longevity yet. Good luck
After the painting is finished, you will want to caulk between the wood and the frame. I used all my random half filled tubes of silicone. It is mostly white, black and beige. Looks pretty strange but well sealed.
I really like that black roofing tar that you get at the big box store for just a few bucks... but of course there are many options... you pick the one you like the best!
Mike...
The quality is remembered long after the price is forgotten, so build your teardrop with the best materials...
I'm with Mike. Black roofing tar beats just about anything for lasting a long time. Elastomeric roof coating is okay also. The spray on undercoating in the rattle can from the automotive section of Wally World is not worth using. Lasts one year tops.
Hope that helps.
Prem
My goal...
_____________________________________________ ...is to live in a trailer.