I've tried to make this work, but I simply can't do it on my own. I want a weakaura that shows me the time until Prydaz activates as a simple timer.
The buff, in case you don't know, is called "Xavaric's Magnum Opus"
The biggest problem with this is that the item itself doesn't show the cooldown, it's only a buff which when gone, doesn't have a replacement that you can track. My attempts so far have mostly resulted in either the timer disappearing with the buff or only starting when it goes away, both of which are fairly inaccurate for tracking it.