OK, that answers alot that you are not fully pulling the trigger. Turn your fluid all the way in, nothing will come out, pull the trigger all the way, then start opening the fluid knob until you get a pattern, keep going until its wet. It is inconsistent if you are not always pulling the trigger the same amount. If you are only going half trigger it makes sense you are getting a small pattern.I don't have a regulator on the gun, so I set the pressure at the wall outlet. When I tried moving the gun further away from the panel for a larger pattern I ended up getting a dry spray effect.
I also have never fully pulled the trigger, only pulling it about half way from the point where the gun starts to discharge paint. Fully pulled back trigger seems to make the deposition far too wet and cause runs. I am not sure how fast or slow I can describe my movement but I don't think it is slow, judging by how fast/slow I have seen painters on YouTube move.
You do not have to waste paint to do this, just use thinner until you see a wider spray pattern, you will just need to open fluid more for the thicker paint.
Just dont ruin that gun spraying alot of primer, get a little Neiko, Go plus or anything with a 1.8-2.0 tip on amazon for about 40 bucks. I think it will help you if you find one with the same knobs you have on the SATA. Some only have 2, but it will get you used to what you move and what changes until you find your happy place.