Stephen-
Beautifully written essay with much detailed information as to how you arrived where you are. It is certainly a great guide for those of us who are flondering with next step "computer" audio decisions.
Do you still have your MacMini away from the audio rack and stream to an Airport Express connected to the DAC via the MR? Do you think this new Gen 5 USB would allow the elimination of the MR/Express and allow you to have the mini on (or near) the rack connected directly to the Gumby via USB?
Thanks for all of this!