Guardian system coordinates in Unity (Quest)

So, I was wondering how does the guardian system determine which way is the positive and negative x and z coordinates? I am trying to set up 2 quests so that players can have a co-location experience with Unity, but the players appear in different orientation despite the guardian system boundaries being exactly the same. I have selected tracking origin to be "Stage", if that helps.

However, if I stand in the same position, look the same way during the whole drawing process and clicking "continue" buttons, I usually get the tracking space to be correct. As much as I would like to think that the orientation is based around player's rotation while confirming ground and guardian system in the setup, that is not 100% reliable. So please tell me, how to reliably get the same guardian system space on both headsets?

Thank you very much