I have the ASI crankcase vacuum/breather setup, which incorporates a T’d off check valve to prevent crankcase pressurization, and I’ve been quite happy with it. There is no oil on the belly and any oil seepage seems to have stopped. On mine, the vent tube going into the exhaust pipe is about 18” from the end of the tailpipe, and I can shine a flashlight up into it to check for coking on the tube. I can also easily remove it when the cowl is off for inspection. My breather line goes directly to the check valve T and exhaust pipe tube assembly - no air oil separator required.