I can't really tell you what the optimum number of coats would be as spraying auto clear is new to me as well. I only mix up 1 1/4 tablespoons at a time. (one tablespoon of resin and 1/4 tablespoon of activator) This is enough to allow me to put between six and eight coats on two bass size lures. (2 1/2 to 3 inches long) I also spray what I call two "coats" at a time. I spray the bait while turning it in my hand and make two revolutions of the bait while spraying. I might also mention that I'm spraying with an airbrush and this might not be possible with the mini HVLP gun as it has a much larger tip size and sprays a much larger volume than what I'm spraying with the airbrush.
So far the baits seem to be holding up pretty well. Since I don't build baits for sale I don't worry about time or materials as much as someone who builds them for sale and is trying to get every pennies worth out of his operation. I know this doesn't give you a specific answer, but as of right now it's the best I can do. Keep us posted on what works best for you.
I will keep eperimenting with different layers of coats and let yall know what works best for me. I can turn the pressue down and the paint flow down on the mini hvlp, but it still may be a little too much for baits. I will still give it a try and see how it goes.