Wright WPL 10V tubes

Does anyone know the original tubes that came with the pre? I have one with an assortment and Id like to roll over to Georges way..From what Ive read about the man he had his reasons. Usually sound! (no pun intended)
for the wpl 10v -- 6em7--6er5--6x4.you have a really nice little pre with a really nice phono stage..good luck