Good point. Last year I played a 20 player game on another map, but with (almost) the same rules having two east sets, two west sets, and a shared set. At the beginning I tried to trade with the other side of the map, but that didn't work. So after two rounds I traded with players of my own side, what worked much better. I hadn't time to trade full sets with players on the other side because we had only 10 minutes to trade in one round.
But with 12-15 players we can make one east set, one west set, and two shared sets.
Quote:
One problem with merging the stacks is when reshuffling a stack with 2 non-tradable calamities. Would they both go to the bottom of the stack? If so, that would mean they always come out in pairs.
A solution to this is to still create an east stack and a west stack, but to shuffle all tradable cards together and in the end divide it into two equal-sized stacks. The non-tradable calamities are put at the bottom of the stack where it belongs.