Is there a clear example of the difference between these two succession laws? I understand that the major difference between confederate partition and regular partition is that with confederate partition it will automatically create new titles. This can split you realm if, for example, your ruler is a king and also has enough of counties from some other kingdom that they could create a new kingdom out of it. Even if they don't create that new kingdom it will be created on succession and handing to their second son. With partition that won't happen and so long as you don't create that second kingdom, your realm won't split.
But what high partition is supposed to do is still a mystery to me. It says here that the player heir will always inherit at least half the late Ruler's titles (it doesn't say that in game which is annoying). But I was on partition and looking at the succession tab I looked to be losing 10 titles on succession. However, after switching to high partition it still says I'll be losing 10 titles. What gives? I'm not even inheriting half of my counties since 7/10 are going to heirs other than my player heir. And of those 7, one is de jure part of my primary empire title, my kingdom title and the one duchy title that my player heir is supposed to get, but yet is still slated to be handed to somebody else which supposedly shouldn't happen.
Also, does it matter what your children already hold? I know you can't grant a title to your heir that they weren't already entitled to, but you can grant to their heir. So, for example, as an emperor I have granted a kingdom to my grandson. Will that count in the partition calculations when my son (after inheriting from me) eventually dies too? (For what it's worth, my current player heir is King of Georgia, a title given to him by my father)