Syncing two packages on two rPis

Correct. It uses the wall clock time combined with the total playlist duration to derive the same starting points across any number of devices involved.

Hopefully soonish that won’t be required as a mechanism to schedule setup assignment is currently in the works. Sneak peek:

There are a few previous topics about that:

They might give you a hint on how things work. Let me know if you have any questions.