Final progress for tonight: got all the basic systems working. Instance master can shuffle the tiles instantly, and udon's positional sync keeps everything in sync across clients, no tricky business. After some fighting with MaterialPropertyBlock, all the tiles render in the same drawcall too.

The tiles are very very tiny compared to Nicky's hands, and I don't think I have the wall layout quite the same as Tanki, plus need to add scoreboards and calls and sounds and shit, but it's all within possibility. The prefab shouldn't have any issues being in the scene multiple times either, so could have a full parlor in an instance.

Shuffle technique is really straightforward, so could do a superior murrican texas holdem map as well. Would need some better UI for chip mangement though besides picking them up one at a time.