UPDATE: Illustrious version is now available. Do note that the trigger words are different for Pony and Illustrious. It's "Diancie" for Pony and "WnDnc" for Illustrious.
This one took a whole bunch of attempts and it can still be finicky. The diamond princess is very demanding, it would seem 💎
EDIT: The Illustrious version does work better though!
I'd recommend generally using the Pony version at a strength of about 0.8.
Helpful tags:
Look at the version info on the right!