It sounds like you need to restrict the oiling to the rockers on the shaft mounted motor
I have a Victor headed motor with shaft rockers and a Gee Zee vacuum pump that only pulls 5.0 inches at RPM and it gets mostly condensation in it with the baffle under the pickup and bypass fittings around 8 inches long with multiple 3/8 holes drill in it.
My next motor will have a Moroso 4 vane vauum pump with Jesel paired shaft rocker system that pushrod and spray bar oiling, hopefully I can figure out a system to help pull air only out of the motor with minimum oil