Oh why am i only seeing this post now @Aussie Ora! haha.
How have you been doing them sense? Have you had another go?
I quite often do pork belly on the KK. I am doing one tonight in fact.
Like you mentioned, cutting too deep through the skin will not work well for crackle. Cutting just enough is the trick.
I am not so organised these days and dont get around to salting it the night before. I do however pour boiling hot water over the rind before i salt it before putting it onto the KK.
The trick is to cook it enough, but not too much so the meat is ruined. Id much rather have a good cook on the meat than the best crackle you can cook with over cooked meat.