Totally understand that. Urethane, and the isocynate component in particular, is very toxic and not something you want to mess with unprotected.
If you are set on that route, I would highly recommend the Alkyd 7400 paints that Rustoleum makes. You can get them at Fastenal or some other places and probably online as well. Probably about $40/gallon. I have sprayed, brushed, and rolled it on with great results - I usually reduce it 50% with lacquer thinner to make it dry faster if I'm spraying (the label says no more than 5% though.

) I would maybe experiment with Japan Drier if you roll or brush on, or just apply it straight and let it sit for a week or more. It kind of self levels that way too, you may not need to do much if any wet sanding.
Not sure what to recommend for primer under it though. Probably want to use an etch primer over any bare metal, maybe an epoxy primer over that. 2k epoxy is a little safer to deal with than 2k urethane. When I was researching primers it seemed like a lot of people like to use SPI epoxy primer and it's reasonably priced.