Canary 906 Pre amp Question

Hey guys, my canary 906 has 4 6sn7 tubes...2 driver and 2 follower..i want to roll some tubes but it is a waste to roll the follower tubes...anyone know which are which inside the unit??..which are driver which are follower....front ones..back ones etc..anticipated thanks, Dan
take a picture of the LS box and I can tell you which one's which. Typical 2 stage gain + SRPP follower config.