Global Cooldown Icon Frame Overlay.
This is a transparent square frame with a semi-transparent clockwise animation simulating the exact same visual effect at the default Blizzard global cooldown.
The frame strata is set to "fullscreen" so it should sit on top of most weakauras.
To Install:
1. Load In Weakaura String and drag into group if required.
2. Change positioning of GCD overlay so it is over the top of the target icon frame that you wish to show the GCD on.
3. If you need to adjust the size of the WA, in the settings select the "Display" tab and then adjust the "Width" and "Height" under "Position Settings" near the bottom.
Please see attached screenshot for a view of which settings i refer to above.