Is there any particular reason to use the coax output of the Quick 6? As far as I'm aware, the audio permitted over that connection will be identical to the audio out of the coax of the Oppo, except the audio from the Quick 6 will have undergone a transmission via jittery HDMI interface first?

If you wanted the hi-res soundtracks, you'd probably be best off with an HD621.

HC: 861v4/ID40/LPS, DSP5000, DSP5000VC, DSP3100, SW1600, HD621, Oppo BDP-105, Sony VPL-HW55ES
2-Channel: Oppo BDP-105, TEAC VRDS-7/Trichord Clock 3/PSU, 551, Quad 303, Harbeth Compact 7ES-3, Kimber cables, Russ Andrews mains and supports.
Previous Meridian: 5000C, 5200SL, 7200.2, 6000, 562V.2, 568.2mm, 800v4, 808.2i, 818v2/v3, 861v8, 502