Scott,
A couple things. I have used Gustard dacs, the X26 PRO and the A26. Both of these produce an excellent sound overall but are slightly overly bright in the trebles. Since you have their master clock, the solution for me was to use the sine wave connections. You may lose a bit of the amplitude of the sound image but gain a lot in musicality without hurting your ears on long listening sessions. Anyway, that was my experience in the house of stereo. Since I switched to an Audio Mirror Tubadour V tube dac, my master clock is back on square wave. Also, if you keep the Gustard dac, copper wires are a much better match than anything silver imo. As a side note, with the Tubadour V, I now was able to incorporate some pure silver wires. Everything matters and finding the right combos is just a trial and error thing. Enjoy the journey.