I'm looking for a specific idea. here's an example of how the format works:

8:00 AM June 1, 1977 (Sirius has just started eating when an owl drops the note in his food)

Not-so-dear Sirius,
I am not sure whether I can live with someone who takes pleasure in my pain and names their owl after themselves. Alas, I have no choice unless I wish to be homeless. Your answer to my questions about James was yes. Does that mean he is living with us or with Lily? You thoroughly confuse me sometimes. I must ask- did Kreacher drop you on your head when you were a wee lad?

Worried about your sanity,
edit: as you can see, I'm writing in no particular order