Hi Tim
a heavy cam with battery compartement might move, meanwhile the magic arm might could be be strong enough with a light one, having a small lense.
If you intent to have a very precise orientation of the cam, it rather looks to be difficult.
I used one for a while, but I wouldn't mount my 1 Ds-2 on it.
So I'd mount the cam with a homemade "groundplate" with a 3/8 screw, and a tripod's head on the bike. You know welders, dont' you ;-)
On the
manfrotto site its listed in the Lighting Support Systems, for holding a umbrella, etc