Not too uncommon actually, hence the 6L6/EL34 bias toggle on the chassis - I've run 6L6 but found they lacked the mid punch of an EL34, but offered really nice top-end. I believe the transition to 77 style tubesets was to kinda offer a parlay between both camps of tubes - the mid grunt and some heft in the lower ranges like that of an EL34, with a more defined top end and sparkle like that of the 6L6.
Anything flies in the VH4 - it's really up to the end users ears. That's the right tube - the one that makes you wanna play more. Simple.