The Rab knows his stuff. Many amps are not worth the effort of nos tubes, they are often ‘voiced’ to sound best\ok with modern products, or their affect on sound is no more than ornamental. I think pathos are not one I’ve tried but their circuit is unusual, not sure if it responds to nos kit.
At top end all usual comments about German tubes holds true, valvo are a good bet, unfashionable but good value. Personally in last three amps I ended up with 2 each seimens and amperex, I like the blend of poppy amperex and soulful seimens . Prob most expensive as well. Order of use depends on what I’ve got, at moment its seimens longplates and bugle boys. A good value option are rca tubes , the 82 clear tops are Musical bargains, and 83 black plates are good value. Both fraction of cost of euro produce.