Which Preamp Tube is most consequential: Input or Gain

I've just gotten a pair of 1950s Tung-Sols for my Schiit Freya to replace two of the stock Russian NOS 6SN7. I will try them in both positions, but is there a typical position of more impact in terms of rolling preamp tubes in the input vs. gain positions? Thanks for any experience you'd like to share.