[kellishaver]

However, it makes it difficult to drop a cloister into just the perfect spot...

[Stormbringer]

That is true whenever the piece will be matching two different sides, you'll have to pull it apart on at least one line (column/row).

However, since the pieces slide together instead of locking together I don't see that as much of a problem.

The bigger problem would be pulling them out of the sack at 'random' :D