I find it's all in the prep for good paint work. I'm no pro but I would do the prep you said with an 800 wet sand and then do a light second wet sand before a second coat of paint. Then follow it up with at least three coats of clearcoat.
Here's the company http://www.automotivetouchup.com/
I used for my dash panel paint. They sell in quarts and in aerosol cans. Clearcoat too. Give them a paint code and they'll give you what you need.