I am running the stock camber locations still. So I believe that is the bottom inner hole.
You should try the chassis mod on the rear, really helps on the bumps.
As for gearing I was running 23 / 67 on a 19T motor Reedy Quad Mag. Probably would have run 24 / 70 . For dual mags like the Chameleon based ones, I can see running lower. The Reedy really puts out the torque. I may just get a full mod of there motors.
As for the mount, try threadlock on the screw and maybe a slightly smaller shim in the mount.
I still don't run the shim but I don't torque it down hard either. not recommended but it works. I would say unless you can get the Kose mount, go with the machined alloy cam as that is supposed to stay in better. In the pic I posted ( not my car , I wish! ) that's what it looks like they are running and word is that it holds better.
My new LHS and track shop is going to look into the aftermarket stuff as well as the hop up stuff and see how much it will be .