It's in beta test right now and all is going well :)
With the embed-code scrollers and product grids now all sharing the same styling, I've brought out the place where you set the styling to its own panel. It appears above the area that displays the products you're currently working with...
..but only when you're using one of the embed-code grid or scroller promotion methods, as that's the only time it applies. For other promotion methods, you won't see it.
This just leaves the embed-code slideshows to be brought into line.
Click / tap to take the current Nifty Promo Control Panel for a spin