Anyone use a DF-17 adjustable PCV?

Kind of missing the point here... the amount of blowby changes with rpm and load. So does the vacuum. And the volume of air going into the engine obviously varies too, so running the blowby back into the intake would change the AFR.
A fixed valve can be adjusted to work at one point on the curve only - which can be at idle, of course. But tip-in is important too.