Recommendation from Doug's Tubes that I went with, sounds great:
V1: Input gain stages to all channels, first gain stages of clean/vintage channels (channels 1 and 2)
Ruby 12AX7AC5 slect HG+
V2: First and second gain stages of overdrive channels (3 and 4) Tung-Sol
V3: Second and third gain stages of overdrive channels Penta 12AX7M
V4: Third gain stage and cathode follower of overdrive channels Penta Labs 7025F
V5: Contour circuit buffers for overdrive channels Ruby 12AX7AC5 select HG
V6: Reverb drive and return Ruby 12AX7AC5 select
V7: Effects send buffer and effects return mixer Ruby 12AX7AC5 select
V8: Phase splitter Sovtek LPS