FWIW, I use an HVLP system. The exact settings vary from color to color. Water-based paints (like Nelsons, and also latex, which I've used, too) seem to be picky about settings, so you have to experiment on some test panels until you get it right. Klass Kote epoxy doesn't seem to be nearly so sensitive about settings, but it does produce fumes which annoy my wife to no end. My recollection is that I thinned Nelsons (with distilled water) close to 50-50 and gave the gun a thorough cleaning between coats. It also went on pretty well with a foam brush, which was how I did the base coats. When spraying latex I've used automotive windshield washer fluid for thinner. It's even cheaper than distilled water. Might work with Nelson's, too, but I haven't tried yet.

My experience with Nelson's instructions (this was years ago and they may have changed) was that they had all the info you needed, but they weren't very clear. You had instructions, then additional instructions and then answers to questions. All together, kind of disorganized. I ended up going through them, underlining the key things, then pasting together a revised list of what to do. (Which unfortunately I don't have handy.) Once you get it figured out, it's great stuff.