I've decided - without even doing the test - to do two things:
1. I'm going to buy the Emotiva XDA-2 DAC, and
2. I'm also going to send one ZP90 to Wyred-4-Sound for modification. I want the digital out on the ZP90 to upsample to 24/96.
The DAC will feed a Conrad Johnson PV-15 -> CJ MF-2500A -> Paradigm Studio 100s.
The system is coming along nicely in the design phase, and I thank the OP and everyone else in this thread for their input & findings.
Cheers,
Z