How do you fit that entire prompt in the customized instructions ?

Some of it is in my customized instructions, some of it I fed pieces in at a time saying "remember this please:" so it goes into Memories.

I'm not entirely clear on the mechanism by which memories make it into context, so it's possible some of it isn't all the time, but it does seem to be working reasonably.

Again, it's not as good as Claude when it comes to writing "not like an AI". But it's significantly better than it was.