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.
Check the ME wagner instructions. My recollection is that on low vacuum engines, the recommendation is to set it up with the fixed orifice.
In which case you can test your theory by experimenting with a fixed orifice in the same situations where its dying now.
Posted some ballpark fixed diameter sizes here, which will give you a starting point.
PCV Flow Rates