Dave,

I have attached a photo of the drain from the turbo on my Renesis test stand.  The orange fire sleeve covers a section of 1986 13B stock oil cooler hose that connects the turbo drain flange to an oil level sensor port (also 1986 13B) which is installed below the oil level in a custom oil pan that I built.  There is a steel tube brazed to the bottom of the turbo oil drain as close as possible to the drain flange.  There is a hose connected to this steel tube which is leads to a crankcase vent port near the oil filler location.  This makes the fire sleeved hose essentially an extension of the oil pan where the turbo drains into it above the oil level in the pan.  No air lock should occur due to the connection to the crankcase vent.  This has worked for me so far.  I initially had a scavenge pump to return the turbo drain oil to the crankcase, but I decided to try the vented drain to simplify things.

I have had no oil coming from the RD1B input shaft seal in about 500 flight hours on my NA 13B installation.  The drain is a -6 aluminum tube with a slight downhill slope from the RD drain to the side of a rotor housing leg.  A 5/8" id crankcase vent is installed in the center iron where the stock oil filler standpipe was originally located.  I haven't measured the crankcase pressure under WOT throttle conditions.  Is there any possibility that crankcase pressure is contributing to the oil leaking by your RD seal?