Stay away from the Clockwork tank.
Acerbis is perfect, as Ned mentioned.
As for the stabilizer- I have two 2012 500 EXCs. I didn't think I needed a stabilizer so ran about 20 hours on one with a stabilizer and 20 on the other without a stabilizer.
While I do not think they are necessary, I must say that riding the one with the stabilizer is far less fatiguing. I'm riding primarily desert stuff in west CO and eastern UT with some initial riding in the San Juans.
Great write up Ned.