B3K into the AO (big one)
AO for a warm, gritty always on for rock sound - then pound it with the B3K.
I tried the other way too - but I liked it this way better.
I like the Duality - but it is very in your face.
The Alpha-Omega may suit etter if you want control over the gain. It's a different flavour but more adaptable too.
My backup is a 2.2 lb Tecamp.
It's so light that it is not a hassle to bring it with me, but it would be very unprofessional if my main amp went bang and I couldn't continue. So I take it.
I'm currently trying to nail Zoot Suit Riot by the Cherry Poppin' Daddies.
I've got to perform it on 15th December so I should really do more practice. Rehearsals are going reasonably well though.
If they are good for 5000 hours perhaps something else is making you think it might be a dodgy tube?
Playing amped for 5 hours per week = 260 hours per year = life span of 19 and a bit years.
How old is it?