@ben@brody the one in engine right now simply does not work. It would be faster to simply point an engineer at a unity and say "like that". They're not even close to usable right now.
The behavior is such that even if you get it working, you then can't control the relative pixel size, it's like- utterly bizarre.
Oh and it stretches instead of tiles on the slices, to boot!
It basically only works for tiny rounded corner solid color "laser" style windows. Which checks out I guess, that's all Unreal games really ever bothered having.