Some people do not have to work for a living and others do not live in the real world LOL. They must either be a merchant banker or work for the American depatrment of bullsh!t.
V
You hit the nail on head 'V'.
I'm sure I have seen these and many other 'crazy toobs' in various old amps that come through here.
A guy I know bought an old Wasp 200 head, yanked the 4 x GEC KT88's, sold em for 4 x amp price.
He reckons the new tubes sounded better - he was a happy camper