i use the same gun and omni epoxy, use a 1.4 tip and about 20-30 lbs at the gun inlet, dial down the pattern to about 8 - 10 inches, reduce with up to 10 % acetone...and spray fairly slow to keep it wet, ..
mp 170 only uses one catalyst mp175. so not sure what the 70 degree is...
also for small areas, i"ll set a pattern at about 4 " tall and just dial the needle to allow a good wet spray , 4-6 inches from surface..
tech sheet is here..