For me, first pass under 50 micron after heads. If I am not at 12 micron when I start to switch to mains, I fucked up. 7 to 9 micron is a happy spot for me all the way through mains. No leaks and better starting material than most. 5L full bore, dual cold trap system with a 7.5 cfm roughing pump and a 21.5 cfm mains pump.