Bob, you are right, wet sanding the primer is the normal thing to do. You can use prepsol (available from automotive paint stores) to clean your primer. Or you can just clean it more with water. 600 grit is pretty fine for prep work. I don't go over 400 on the primer. The reason for this is that the paint needs something to grip to. So having your primer too smooth can cause problems. There are others that don't go over 320 grit on the primer.
The lightest type of paint out there is dope. But it takes many coats too to achieve the desired results. Automotive type paints give very high gloss finishes, you would need to check with a dealer for details. You want something not too toxic. Some of those type paints need a full respirator to use. Also look up klassKote on the net. Dave Platt recommends this stuff. It's like the old K&B paint, a two part epoxy enamel.
http://klasskote.com/index.html
Good luck.