I have used Preval sprayers to epoxy prime all sorts of small parts and even larger things in sections. I would feel 100% safe painting something smaller like a hood hinge, bumper brackets and so on with a Preval. Not so sure you would get a nice blend going up against an already painted surface with one???

They are very finicky with the amount of solvent. Not enough and it's orange peel city. Couple ounces more and you run the risk of runs and sags. With primer it's no big deal as you can sand flaws back out. Paint is just not as forgiving.