Here is mein-blau tv’s explanation translated from German to English using Google. Few grammatical edits for clarification ~ Big Thanks to Mister Mein-Blau TV 
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EASIER AND MORE ACCURATE
it didn’t help me personally, because the mere fact that I don’t have a controller as a SIM player makes the whole video useless. The fact that the IPD value is not really taken into account and that everything goes a little by thumb doesn’t really help either. Glasses off and on and then … I guess it will fit?
I found something that you can do with your Pimax 8Kx, to set the absolute optimal IPD value and thus get the perfectly sharp picture WITHOUT this imprecise controller attempt with glasses up and down etc.
First you need your IPD values from an optician. If you have this, you set exactly this with the small wheel on the Pimax. The most precise measurement is very important.
Then you need this file :-
Then make a backup copy of pimax_default.jpg in C:\Program Files\Pimax\Runtime\resource
Replace the above file with the downloaded image.
Now put on your Pimax headset and the adjustment using the Pitool can begin.
You need to click on the point in the Pi Tool and use the arrow keys on your keyboard to change the numeric values up or down. At first you will see a distorted image vertically and horizontally. But …
Now close the non-dominant eye (the one where you can read less well in normal life) and move the slider until:
a) on your dominant eye (the other eye is closed) the box in the middle is looking straight and pin sharp.
b) Now open both eyes and adjust the left image (move it onto the other) so that it fits the other image 100%, i.e. it is on top of each other. Now you shouldt only see one picture, no distortion or displacement. One line is 100% on the other and lo and behold…
The top picture is ready…
- With both eyes open and the image lined up correctly with no overlap, means the IPD settings are now correct ! *