You know, you've just reminded me that I didn't have preferences like that in here. I used to have it in another post, but never replaced it. I will fix that and add it here, thank you!

Fourthwalling is fine. It won't bother d'Artagnan, he'll just think it's strange. He may get wary/paranoid if you know a lot of detail, but in general, he'd just be pleased anyone remembered enough about his friends' exploits to record them.