Currently the Spark settings seem to be stored on ~/Spark and another file called ~/userdic.tlx is created when Spark is used on OS X.
The “proper” location for folders with user-based settings on Mac OS X would be ~/Library/Application Support/ApplicationName.
While this is an admittedly minor issue, the base ~/ on Mac OS X is generally reserved for what Apple has put there, unless its a .hidden directory.