Hey, riggles. I own the rack version with a Line 6 Pod HD Pro X for processing and I can tell you there is absolutely no room for the reverb tank in an SKB 6 space shallow rack 1SKB-R6S so I don't even connect it. I don't need it with all of the processing power in the Pod. Without the tank everything is a perfect fit, light, transportable and the front and back are gasketed to keep the moisture out.
I'm sure it's a simple transfer from combo to rack but a call to Mesa Boogie would help. They return all calls and emails and should be the same day. I've talked to them a few times and discussed my TC-50 through repeated emails.
