This is a question that applies to the 5-input models (first generation?). Which input do you use?
2nd Gen has 'em, too. I use the "both" input so I can have both pre-volumes in use.
You've seen the videos of me playing mine, those all are "both" input. The bottom two are pass-throughs for slaving more model T's. just sayin'.
Both.
Always both.