FMW, just a comment to your mentioned:
removing all the hearing bias from the test
This is absolutely necessary but not enough.
I think that all your statements, such:
Hi-res" has no audible improvement over redbook 16/44
Outboard DACs have no effect on sonics
Might be affected (just guessing), biased by the weak link in all your non bias auditioning: the "microphone", the most important instrument in those kind of judgments which instrumental error can be easily affected by aging.
For example, just as worst case scenario, when I will get older, one of my "microphone" will be able to register only up to 5kHz sonic frequencies, the other one even lower with even some frequencies falloff in that range. I will start dumping all my Hi res. SACD, DVD-A collection, before off course recording all of them on the old 3.82mm wide magnetic cassette tapes at 4.78 cm/s. And I will come back to this forum and will start spreading my truth based on my non bias auditioning results that it is no audible difference between CD, SACD and my lovely tapes, even going further, will start archiving SACD on the Phonograph Wax cylinders
And will keep mentioning: if you hear the difference, it is either only in your head or your auditioning is biased.....
All the above was more kind of form of sarcasm, not the criticism......