Running DCS Vivladi DIRECT?

Big difference between you and I George. I can easily accept the fact that people can and will choose either approach. If someone prefers DAC direct I don’t 2nd guess their decision (why should I?) . You on the other hand are dogmatic in your opinions and display a tendency to belittle those who do not share your viewpoint or attribute it to "pleasing" coloration. As pointed out previously DACs direct to amps presents their  own inherent coloration and shortcomings, You aren’t experiencing straight wire with gain. Don’t fool yourself. These choices we discuss are "all" sonic tradeoffs.
Cheers,
Charles

By the way the OP ask for "comparisons and to elucidate the differences. This is what folkfreak did in fact do.
Charles 

By the way the OP ask for "comparisons and to elucidate the differences. This is what folkfreak did in fact do.

Well don’t jump on Johndoe’s case for doing just that, forest and trees.

You aren’t experiencing straight wire with gain.

No it’s straight wire with NO gain, even better as there's no gain circuit.

my listening levels for the tracks were between 9.5dB and 14dB cut on the DAC

I'd try the 0.2V output setting on the Vivaldi if you attenuated between 9.5dB and 14dB; this way you'd be able to run the volume control to max, with no more than 5dB of attenuation.

Fair point @seigen but the other consideration is level matching with my phono stage. With the current settings the two need the same rough preamp volume settings and so avoid the danger of playing too loud. 

Gain matching across the entire amplification cascade is an interesting topic and one I’ve previously commented on (albeit in the context of phono)