[MrMCar]

OP: Have you taken into consideration of hot (thin oil) engine VS: cold (thicker oil) engine into the possibility for your leak spot?

 

[MrMCar]

Found these crankcase pressure specs. I'm going to measure my m54 with the CCV bypass and compare.

Connection method:

I don't know who's instructions these are. That's NOT a good tool. Home made from a oil filler cap.
Inaccurate reading 101.
Sounds harsh, but I've made two the same way.
Inaccurate testing will have you chasing your tail like a dog.

I have the factory (metal) tool.
You're better off measuring through the dipstick tube.

 

[MrMCar]

Almost 6.5 inches of Mercury or water.