Play don't starve .
The item stacking is fair, expected, and not too hard.

say you have a stack of 5 items with 100% health
- 500 / 500 (5)
you add one with 49%
- 549 / 600 (6)
you add another with 49%
- 598 / 700 (7) ... so the average health of the whole stack is 85%

note that you aren't ...

Yo don't forget you can just treat multiplayer synchronisation like a data backup. What you are sending is lots of incremental backups, but don't be afraid to send the occasional snapshot/keyframe which has the full status of things (or a bunch of things). Ie. when a new user connects you can start ...

Even lengths or granular placement of train stations to enable bi-directional train stations: