[Zeke]

Model T's were painted with a camel hair brush. The paint was not today's paint, obviously, and flowed very nicely. In order to hand apply paint, it has to have time to flow, which is to say also collect dust. A straight enamel, not acrylic, of the old fashioned order, does this well. Takes forever to set up an dry, but levels very well.

So, I would say use very slow, hot weather thinner and you could do this in a very clean and calm environment using today's material. It's kinda like the differnce between varnish and polyurethane.