How do I create weak aura buttons that are the same as the default icons in the action bar?
i.e. I want to have a Barbed Shot icon that is there all the time, goes gray on cooldown, and has the sparkly highlight when there is a proc.
Do I need several layered WA buttons? Or can I create this with a single icon aura?
tyvm 
There are different ways to do this.
One is to have a separate icon for each state of Barbed Shot (2 charges, 1 charge, Proc’d, no charges). That’s probably the simplest.
Another is to have separate triggers for each state and use the additional actions feature to turn on whichever state’s display is active.
There isn’t really a right answer to this. It’s just a matter of what you can wrap your head around as far as putting it together goes.
thank you!!