Great question.   I never got a lot of great info on how much oil flow I should be feeding to turbo.  I take the supply from the oil outlet on the top, spark plug side of the front side housing.  I run it through an electrically operated shut-off valve in case the turbo fails in flight.  I originally used a #30 hole in a plate of aluminum as a restrictor.  Later I decided to omit the restrictor and just rely on the shutoff valve and AN-4 plumbing to provide enough restriction.  

I have no idea if my system is correct, and I do get quite a bit of oil seepage and mist coming from the area of the turbo, but at least the most recent turbo has about 700 hrs on it.

Dave Leonard