when i took out the VIS motors they have a button vent on the bottom of them which allows the oil in. I don't know why you just dont block it off it?

Letting the oil vapour through should lubricate those pivot points, which is good! It is only a problem when other particulates get it and create a grinding paste, but if you run a decent induction system that should never happen.

i dont suppose you got hold of a rover 800 cast version with double throttle bodies, whether that is any better i doubt it but it wont break!