One thing I would like to add; 12 close votes per day is not enough; I would prefer you to increase the limits to 30.
I make a habit of only closing questions that have 4 close votes, and there was not a singlee day when 12 close votes was enough; there are just too many lousy questions, inappropriate questions, duplicated questions, belongs-on-superuser/serverfault questions that require merciless closing.
In addition, to create incentive to close questions, you should really, really award badges for users who already close a certain number of questionsbadges for users who already close a certain number of questions. Better yet, this set of badges should be able to be awarded numerous times.