[Q] Move from CM11 (JBBL) to CM12 (KKBL) topic

Apologies if this has been asked before but I can't seem to find the answer. I've read this post but it seems more complicated than it needs to be...

I've got an unlocked, rooted xt925.

I'm on CM11 JBBL nightlies (with CWM Recovery) and I want to move to CM12, which I believe means I need to revert from JBBL to KKBL first.

Is that correct?

If so, can I just download the KKBL firmware and flash it? Or do I have to use some other process? I'm on a Mac so I can't use PC-based tools (although I can use adb etc).

And where can I download KBBL from?? And will I lose root?

Thanks...