There is a fixed limit of around 25 feet square for any given guardian. However you can create 2x2 row of guardians. And it seems the quest actually stores them in history. And it actually knows to autoselect the next guardian.
The problem is there is nothing to disable the popup asking you to confirm guardian as you step out of one and into another. There also needs to be an event that fires off telling you that the quest has reset it's tracking position so I know the tracking has been zeroed out