Tom,
When you mount the chokes, they should probably be isolated from the chassis plate. As for gro9unding, I'd try it both ways, but a la bottlehead -- a piece of buss wire taken back to the common ground point.
HTH,
Jim
Jim Rebman -- recovering audiophile
Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).
s.e.x. 2.1 under construction. Want list: Stereomour II
All ICs homemade (speaker and power next)