Speaking of Caldera, I finally just tried the Caldera suedes on the VO and wow! Stage is immediately wider and more open and bass quantity makes it like another new headphone. I've been using Universe suede probably 90% of the time and they have been my favorite headphones until I got the Caldera. While I've never found VO bass lacking, between the Caldera and the 1266TC being my newest headphones, I've gotten used to bass being on another level up from the ZMF dynamics. I think the Caldera suedes even push vocals a bit more forward. They're also pretty great on the TC too.I'm deep into critical Caldera listening at this time & have been for weeks (preparing to write a review). Between ~200 hrs burn-in, then cycling through 4 sets of ZMF pads, then comparing to other planars, it has pushed aside all other headhphones--including my favorite headphone ever, the silkwood VO.
I look forward so much to resuming listening to the VO. There's something special about the VO that always grabs me all over again when I return to it. The sound is like a benign, pleasing hallucination, perhaps a fever dream. I forget it when I don't hear it, but as soon as I hear it again, off I go on that VO magic carpet ride.
The VO's combination of speed, resolution, slight warmth, tonal & timbral truth, and eerie 3D-ness of every note is unique, in my experience. No other headphone quite does this, not even really great ones.
No idea about Lambskin or cowhide Caldera pads, but if you've got any Caldera pads on hand it's definitely worth trying them out on the VO. I ordered a set of Caldera suedes immediately!