Jet,

thanks for taking the time to post your findings. I'll take note of your experiences for future projects.

I've been using Latex as a primer for about 15 years. Have never been disappointed. However, I've always brushed, never sprayed. With a good quality brush, the brush yields a finish very similar to spray. My shop is fairly small. and it doesn't take long for overspray to fog the place.

A couple points that I've not seem covered in the articles and pots I've read on the subject:
Latex is a rubber material. As it dries, the fillers rise to the surface while the rubber material settles to the bottom. What that means is that it doesn't sand like other materials. Sanding is limited to a slight smoothing of the surface with 360 (there 'bouts). Once the surface finds are sanded down, what's left is rubber, and sands about like rubber. So, the best way of dealing with surface flaws that might require sanding is to avoid them to begin with. If and when I get a sag, I wipe it out with a a damp rag and continue on. The layers of paint are being applied in thin coats, so chances are, the wipe-out will never show in the final result.