As you probably know I run a Two.2 with the WS, of course, my vol is permanently disabled. However, I did run my WS for a while with my XDA-1 dac, and I had its volume turned all the way up, and it sounded great. I'm pretty sure I remember Seth saying with the Sensation volume all the way up it is like 99.9% bypassed. If it would make you feel any better, I'm sure Jason can wire it permanently off for you.
Either way I guarantee you will totally love the combo, you should do it. It's not like there's going to be an enormous loss of quality, if any.