After rereading this thread, I can safely say your Compressor is the weak spot in your set up.
I started out with a horizontal tank compressor that couldn't satisfy the CFM requirements of the spray gun and tools I was using. It ran constantly when using my DA, which wouldn't run more than 5 minutes before I had to wait for the compressor to catch up. At the time I was using EVO spray guns that only needed minimal CFM to run but I was finding my spray pattern would change after a few passes on a panel.
It was then that I went online to auto painting websites looking for advice. Fortunately I found out about SPI Epoxy Primer during that time but I also began to understand the importance of having a compressor that puts out at least 20-30% more CFM than my gun requires. This prevents any changes in the spray pattern when the tank begins to empty and any pulsations when the compressor kicks on.
That is when I sold my old compressor and bought the one I am still using today. It cost just over $1000 but that was over a decade ago and I was really stressed to spend that much at the time. The difference was amazing and I am so glad I bit the bullet and spent the money, hence my tendency to immediately suggest a bigger compressor to anyone trying to get by with "just enough."
It sounds as though your are committed to giving the compressor you have a try and I understand that, however if you find yourself constantly struggling to get good results with your spray gun, it's probably the compressor and not the gun.
Just my $00.02 and worth everything you paid for it.
