I don't have any issue with the use of tube buffers. Of course the traditional use of a buffer, be it tube or solid state, is as an impedance matching device, hence the name.
Obviously, in the all Exposure system you don't have an impedance mismatch and are using the tube buffer as a sound enhancement device. I have no issue with that as we use cables, room treatment, phono cartridges and many other things as tone controls. And I did not ask for a justification of its use, nor did I call into question your use of the device.
I simply asked because, although I own a tube buffer, I don't use it and my electronics are otherwise similar to yours so I was simply trying to get a better understanding of how your observations might translate to my system. Clearly, that is not to be; enjoy your rig and thanks again for an excellent review.