Not a whole lot. High flow barbs allow for a lower operating pressure. The lowest possible dwell as well which would be the recomended dwell for your solenoid. These two things combined made a little difference in the efficiency of my marker.
My LPR is @ 55psi.
Dwell is @ 12ms. for Humphreys solenoid.
I did run it at 8ms for a while but bumped up because of recomendations from those more knowledgable than I.