Found what I was looking for....
1-4 hg. (0.49 to 1.9 psi) Is normal operation.
Switch alarms at 5.5 hg. (2.7 psi)
my reserve tank
15’ of 3/8” fuel line = ~1.5 psi
16” head (empty) = ~0.4
Racor separator filter, clean = 0.6 psi
Clean system drop = 2.5 psi
Not much room to play with. A dirty...