I finally worked out a good technique for spraying this, so thought I’d add my experience for future searches.
I’d suffered the same pooling/running as above, which I’d been trying to avoid by reducing psi in steps. I got down to 10 psi and still had the same issues, with a further lack of atomisation causing blobs to appear all over the surface. Before giving up for good, I thought I’d experiment on a mule for a while.
In an effort to just try something different, I went back up to 30 psi to achieve nice atomisation. Then experimented with distance.
I found I can achieve really nice fine results with 30 psi, and holding the model at arms length away from the airbrush. This is with the trigger just edged back a fraction to start spraying. Pooling and running don’t seem to occur at that distance unless you’re careless, but the mist is still wet enough to give a very smooth finish. Coverage is pretty good, I find that two passes are enough. I’m not sure how you’d get in close to handle intakes etc. maybe a prepass with Tamiya XF16 would be enough there.
All the above is with an HP.CS and standard 0.35 nozzle.