Agreed.
With the gun empty, I turn the fluid knob all the way out. Then pull the trigger full open and hold it while turning the fluid knob back in.
When I feel the fluid knob start to push on the handle, I release the trigger and then turn the fluid knob another 1/2 turn in, this will get you close.
Hook up the air supply and with a gauge at the gun, pull the trigger full open and adjust your PSI to 30 PSI. Put some primer in the gun and spray a test pattern on some masking paper. To do this, pull the trigger full open for 1 second and release. If the pattern looks full and you don't have any runs, you should be good to go.
Once you get it set where you like it - write your settings down in a notebook. It will save you a lot of time in the future.