I've never shot HOK paint, but I'm familiar with it and have several friends who've used it and there isn't anything better out there. It's very pricey, but it's a very fine and beautiful product. The one thing I can tell you about painting and buying products is to pick up the phone and ask questions, don't bother with email. You can't have enough tech support and email is too limiting.
I agree with Mike on the wrinkle/ compatablility issues.. It does happen on very rare occasion, If you do manage to get two completely different chemicals together, But paint manufacturers will throw a disclaimer out there about farting near their paint.
As far as primer colors go, most companies will offer their primers AND sealers-Always spray a sealer before shooting color!!!!- in a variety of colors to compliment your paint color. Ask for what you need, The dealer will help you!