Hi Colin,
Maybe I should clarify what I meant in my earlier post.
Use the SpeakerLink output of the 210 directly into the 5200s. This is for full MQA stereo only, and the coax digital output of the 210 is not used at all.
If you want Trifield, only the coax digital output from the 210 is used (NOT the SpeakerLink connections) and this coax output goes into the G61. The G61 now produces Trifield with all the existing wired connections to the DSPs.
There is no circumstance in which multichannel surround is generated by simultaneous use and wiring of the 210's SmartLink and Coax outputs directly to front and rear DSPs.
I don't have SpeakerKlink DSPs so others can chime in here as I'm making some assumptions about how to utilise both digital inputs on the Master DSP. But my suggestion was:
Keep the G61 and DSP wiring as it was before addition of the 210. For Trifield, the 210 simply becomes another G61 source input, and you use the 210 coax digital output for this. You will not get full MQA in this scenario, but you will get first unfold MQA which makes a nice source for Trifield if you wish.
For fully unfolded MQA, wire the 210 SpeakerLink output directly into the unused input on the Master DSP (if your G61 is a SpeakerLink model, I assume it already uses D1 input on the master DSP. The 210 will then need to go into D2 on the master DSP and you'll need to configure the speaker to activate D2)
I hope that clarifies things.
Cheers
George