Re: dulon polish?
Best I could tell from my research was that it's a polishing system for automotive or marine paints/clearcoats, but is not a finish per se.
Not sure exactly what's in it, but assuming it was compatible, you could spray a nitro/poly and then use Dulon to polish it up to a high gloss.
French polish is very different as it is a method of building up and glossing up a shellac finish by hand-rubbing without the need for buffing or polishing compounds as is needed with nitro/poly. French polishing results in a beautiful shine, but it isn't as durable a finish as a nitro or poly finish.