Comparative gains for tube types on BHK Preamp (12AU7 versus 6922 variants)

Stereophile magazine (back around the time it was released) tested the gain on the XLR outputs for the BHK Preamp as 9.6dB from XLR input to output. That was using the OEM 12AU7 tubes.
Does anyone have an measurements on what gain increase / decrease you’d get using the 6V tubes (obviously with voltage and current jumpers set appropriately) versus the gain with the 12AU& variants?
I know technically that the 6922 / 6dj8 and related tubes have a higher gain structure but I have no idea how that directly relates to the BHK as it is a hybrid tube / mosfet design.