It's been awhile since I checked, but my friend used to use some electric air pump from a Chevrolet application to suck crankcase vapors. Eliminates the need for having to accommodate the belt driven pump into your serpentine system, and the pump is designed for the application. The pump is noisy as hell though. I don't know what is done differently when it's a factory install to quiet that b itch down, but on the race cars that he uses them on, it sounds like a little shop vac or something. because it's a constant pull, I think there isn't a need to install any bleed restrictors and you can otherwise seal up the engine vent system, running just the one (- whatever) hose to it, and vent the gasses ( from the pump) into your breather tank..
I'm watching you deal with this, because I'll have a template when/if my vapor issue becomes a necessity.
If you want, I can call and find out if he's still using these things, on the cars he builds, and what/where they come from.