FWIW, I had the T1 for a month this summer - impressive, but I returned them to try the HE-560. The 560 is even more impressive than the T1, and I have kept them. But honestly, 9 times out 10 I reach for the V6-Stage.
I do believe the Project Ember, with the ability to set the output impedance to .1 Ohms (yes, 1/10th) and gobs of power to spare, has an excellent synergy with these multi-driver IEMs. Better than my Asgard 2, which sits cold these days. Maybe because it can handle the large impedance swings of BA drivers? Also had 4 days with the K10 this summer and it was stunningly sweet and effortless on the Ember. I was left happy with how the V6-Stage approaches the K10's capability without spending $1600.
Don't know if it matters, but my V6-Stage are universal not custom. To get the best soundstage I wear them very shallow, just enough for the silicone tips to seal. I've often wondered how this compares to the deep fit of customs. I guess this bodes well for the new U series.
Just one guy's option on the soundstage vs. full size cans, but not a flippant or completely uninformed one.