Yeah, the pipe is awesome with LR boges, and the supplied batteries are actually pretty damn good..! I easily get a full day out of them.
What about this extender/adapter? 21mm 510 to 510 Extender / Adapter
When i get time i may try the 510 to 510 adapter plus a 510 to eGo adapter i am sure they will come in handy for something if i can't use them with the 601C