Model T preamp gain stages: I purchased some Genelex Gold Lion 12ax7 B759s, and Sovtek, and Mullard 12ax7 to distribute to my 1st and 2nd generation Model Ts. Can anyone provide some literature for selecting the v1, v2, and v3 stages? I am interested in getting the most gain throughout each stage. Any input would be appreciated. I have limited understanding of the technical aspects of this topic.