...were, ironically, Groove Tubes 12AX7-Cs from Amazon, by the time I added in shipping. The JJs Mesa sent me needed to come out for sure - dark and lacking gain. I'm pretty disappointed with Mesa for going this way, actually.
So I ordered them, put them in V3 & V4 of the Triple tonight, and the magic is back! The preamp is currently:
V2: EH (sounds very nice here, actually)
V3 & V4: GT12AX7-C
Have you tried these?