I just went through all this on an '11 300.
The problem with chatter is not in your set-up, so much as the GG's clutch basket is just really noisey when the clutch is slipping. So any situation that makes the clutch slip, like getting on the gas hard at low RPM, will make it chatter. So, though the noise is un-nerving, its normal.
-yes, go with the plain Rotella oil.
-I had to use the anti-squeal x-rings. Still chatters, but much more tolerable.
-all red springs (lighter) will make it lock up sooner and with more authority and should thereby reduce chatter. But that may make too much drag/creep at idle. *note: The x-rings will make more drag at idle.
Its a PITA to lay the bike over and mess with it over and over until you get it right, but don't be afraid to try everything once if you have too until you get it sorted.
Get the Rotella in and do one thing at a time. I suggest this order:
-anti-squeal kit, red springs, adjust gap as required (start with where you were before at 1+3 ticks).
My issue wasn't chatter (though I wish it did so less), it was too much drag at idle. I ended up with Rotella oil, anti-squeal kit in, blue springs, 1 turn + 2 ticks. Works perfect. Again, I have a 300.
Oh, and use a little plain grease (not black moly grease!) on your gasket so you can get your cover off over and over with out goobering it up. Good Luck!!
