OK - at the risk of outraging the Taurus owners out there, I think I've nailed down my preferred combinations.
The Mac Mini will have to 'make do' with
Decibel -> Furutech USB -> HRT microStreamer -> Taurus and
that's the combination I want for the HD800, regardless of everything posted here re coloration and distortion. The Hugo just seems to naturally find it's way onto the bed with my laptop and I've got a new Audioquest mini-USB cable incoming : overall I did prefer coax to either Toslink optical or USB but it wasnt a chasm for me. Happy to use the USB in 'transportable' mode by itself with my other cans, and the microStreamer is a much better DAC than it's sticker would suggest - it just isnt in the same league as the Hugo.
Now if I can just find a use case for these %##@^! LCD-2s