Dan, like Mike said, it's a bit too runny and unpredictable, although clean up is always easy. I've just never thought of using it over either urethanes or enamels. Yes, I would imagine if you drop the PSI down low and spray light coats you can get good coverage.
Thanks for explaining how you use it, and I think it's wonderful you get good results with it, and YES, please do post a couple of examples. Thank you.