I think I'm only getting 2 channels of input because the multi-channel DSPs are not available on the G68 when I scroll through the options with the remote.

Not sure what is the problem at this point.

I made the connection to MD1 so I assume that the coax connections between the HD621 and G68 should be:

1/2 to L/R (Multi digital 2)
3/4 to C/LFR (MD digital 4)
5/6 to Surr (MD digital 6)

Any other thoughts? thx

MD600(2x2TB); iPad Pro
LR. 818v3, 8000SE
HT. 861v8+ID41,HD621; BW 2x802D,HTM1D,4x804S;SVS sub; Mac 5 MC501s; RGP 600Pro, JVC X950; Radiance Pro; Oppo 203
FR. G65, DSP3200-3300 DSW, HD621; Mac MC152; Oppo 103, PDP TCP65VT60, Radiance 2124; RGP1200C
4. G65, DSP3200-3300,HD621; OPPO 83, Radiance XE PDP
5. 818v3; Prime HP Amp; HD800