Benjamin Moore got back to me. They recommended Fresh Start All Purpose Primer 046 and Regal Select Paint. They didn't explain why they thought this would be the best product for my application.
The primer and Paint are both 100% acrylic. Apposed to Rust Scat which is a Polyurethane enamel or monstaliner's "Aliphatic hybrid urethane polymers".
Wouldn't Acrylic be more likely to chip?
My local Ace Hardware caries both. primer=$43/gallon and paint= $73/gallon. so the price seems pretty good and you can choose from any of Benjamin Moors many colors.
Good bit of research. I don't think that either Rust Scat or the Acrylic stuff you mentioned would be prone to chipping. I feel that Rust Scat is pretty hard but not brittle, but I don't really know.
Personally, I wasn't interested in water based house paint that I had to prime. I'm just old fashioned I guess but I wanted something that I perceived to be way more durable, thus the more industrial, oil based enamel. (BM's glossy colour pamphlet on Rust Scat showed it being applied to various really rugged outdoor industrial sites which completely sold me
!!!)
As I mentioned, my local BM guys were very certain that it would work perfectly for my camper, which it did. (They were quite invested in the project, wanting pictures and updates, gotta love small towns!!)
Polyurethane enamel is a bit more demanding in that you have to ensure that you use multiple thin coats, ensuring generous drying time between coats. My paint guys were adamant about this due to the fact that recoating this paint too early will lead to poor/slow drying of the underlying coat which can be a problem. Once my first coat was dry, I pushed the envelope a bit for the second coat and concocted a well mixed slurry of fumed Silica (for bulk/texture) and Rust Scat which I then applied with a small roller, trying to work as much texture into this coat as possible, all the while keeping it as thin as possible. It worked really well. I gave this coat an extra day of drying before two more additional thin coats. Although nothing like the texture you get with Monstaliner, this was kind of the poor man's version.
What you might consider with your project is get a quart of Black tinted Rust Scat and use it for trim. If you don't like it, you wouldn't be out that much. Just a thought. cheers