Low pressure is probably the most important thing. Just enough to lift stuff out of the cut but not enough to inadvertently drive the swarf deeper into the machine.
I have a little in line regulator on an air tank outlet dedicated to blow-gun duties to save adjusting the main one each time I switch to the blow gun. About £5 on impulse from LiDL (where else) but I imagine similar things can be gotten for similar prices from the other usual suspects.
The same impulse buy picked up a similarly cheap manifold with 6 tapped holes which made life far simpler. Two "permanent" QC connections for the sand-blaster and coolant misters as well as the in-line blow gun regulator. Two spare female QC, one for PCL and one for Euro connectors so I can hook up anything easily.
Clive