5HP18 Valve Body rebuild question

[Frank87]

Car: 530iA Sedan Euro
Transmission: ZF5HP18 "088"

I am rebuilding a spare "088" 5HP18 transmission. I already did all the work on the driveline. I plan to rebuild the valve body next week. I will then slot the valve body into my current transmission (which runs excellent by the way) to ensure I did not screw up on the valve body so that, when installing the complete transmission + valve body, I know that when a problem arises, it's in the driveline. I have 2 problems:

Problem 1: I do not know the diameter of the one way check ball.
There is a one way check valve used when the manual "2" position is slected with the lever. I have ordered the part from ZF but I only get the plant pot, spring and cap. No ball. I also want to start using an aluminum ball but I do not know the diameter. I have looked in various forums and came across the same question asked by Shogun. A reply was that the ball measured about 4.56mm but afaik that was a ball from a used valve body so it may already have worn down to 4.56.

Problem 2: I do not know how to calibrate the pressure regulator correctly.
The 5HP18 repair manual states that the pressure regulator needs to be adjusted after any work done to the valve body or internals of the transmission. The repair manual does not say what or how to do this. I have not touched the pressure regulator yet. The pressure regulator is located in the solenoid block. It has a large torx screw on it. Any info on how to calibrate this piece is welcome.

Any help or advice would be great. I have a large amount of photo's to share on how to strip the driveline. I will upload these somewhere on this forum.