Yeah...the 1.8 mm tip is a big part of the problem. It allows you to put up too much paint per pass. One can try compensating somewhat by increasing the speed by which they move across the surface, as well as the distance one shoots from (going out to 14"-16"), but there are other things to consider trying if you can experiment on a spare surface.
That sort of Gravity Fed / Compressor Fed HVLP has a few adjustments that Electrics do not.
- Locate the Fluid Control Knob and turn it back at least 2 full rotations
- Locate the Air Supply Knob and also stop it down slightly, while keeping the air pressure delivered at the Gun at 45 lb psi
I would shy away from trying to use the 0.8 mm Needle. Doing so would require thinning the Mix even more while increasing the air pressure to make certain your Paint mixture is getting fully atomized. It can be a valid method but it would require experimentation before you try to hit the surface.
Recently, because of the size area involved, I painted a 13' wide x 9' tall Wall sized Screen using a 1.5 mm needle on my Earlex / Wagner Hybrid rig. I ran it with the Fluid Supply wide open, but I moved across the surface at a rapid shuffle (4' per sec.), keeping at least 12"-14" away. Even so I could plainly see just how much paint was exiting the Gun compared to when a 1.0 mm needle was employed. So much I hastened to get my Pole Fan going to set / dry the droplets ASAP.
, I would feel safe to say that you didn't so much see a dispersed pattern of droplets as much as you saw a fairly solid stripe of paint being laid down....having accomplished full coverage in just 4 coats. And yep...I imagine the Screen still looks very good....lot's of extra gain comes off such a surface. But as you already stated, it does have some drawbacks, and such things are not to be tolerated! They don't need to be tolerated! Not when doing is correctly is so very simple to do.
All that said...a "Hit or Miss" or guesswork approach is not something to try. There are real and valid reasons I've stressed repeatedly that a 1.5 mm needle size should be the Maximum considered to be applicable...and that using a 1.0 mm is a way to assure that if anything, one might have to apply 2-3 extra coats to get complete coverage.
One should always live by the mandate:
The Gun giveth...but the Painter cannot taketh away.
screen above looks to have been done correctly,
albeit his attempt to correct a issue before asking was a wrong approach. But in many ways the exact same solution that would have addressed his issue is the one I've recommended to you. You did ask first before proceeding.....so now it's up to you to decide what approach to consider to use.
As for me and my opinion..................