That has changed recently, there is now an official support article on how to tighten the bearings:
Be very careful when reassembling, it’s easy to bend the microswitch when inserting the carriage.
Personally, I find the precise distances specified impossible to use constructively - instead I would recommend tightening the bearings so that a small amount of force is required to insert the bearings. That is, a small amount of compression to lightly ‘pop’ the bearings onto the rails, but otherwise it slides freely. The carriage can be inserted in both orientations for testing that, you don’t have to thread it into the lead screw to just adjust and test the bearings.