Not exactly sure what to tell you about your idea on the plumbing end, but I
can tell you (in case you don't already know) that the turbo definitely
has to have a good amount of oil under pressure to keep the bearings lubed because of the RPM that the bearings might be spinning. The oil pressure has to be up there during operation and can only start dropping off as the turbo is winding down. I've never had an engine of any kind with a turbo, but I've worked on and operated the Army equipment with turbos and there is always that info plate on the dash that tells you about allowing 5 minutes of idle before moving out with the equipment and 5 minutes of idle before shutting the engine down. Just thought I'd throw that in there.
Take care, Bill