I use (and enjoy) MD 108T for quite some time but I think it's time to change tubes. MD stock "CryoValve" 6922/ECC88 should be the first choice but based on a review (by Robert H. Levi) in Positive Feedback (issue 22) that suggested GE or RCA 5751, I'm thinking about other possibilities too. Any Magnum Dynalab users here with tube rolling experiences?