[Didymus]

The standard mix for automotive urethanes is 1 part paint to 1 part reducer. That's probably what HOK uses. I agree with MPWR that you can probably reduce it a bit more.

One of the great things about urethane base is the way it covers. A very thin coat completely hides the color or primer that's underneath it, so it can be thinned quite a bit. If you over-thin it a bit, no harm done. Just wait a few minutes and give it another coat. You'll need to clear coat over it, of course, unless you want a satin finish.

I only use non-metallics, so it's much cheaper for me to buy unthinned Dupont single-part urethane touch-up paint ($14 for 2 oz) and then thin it 1:1+ myself. I've found that regular lacquer thinner works just as well as urethane reducer, and it seems a lot less toxic.

Ddms