Hey Wizard,
Those are good questions. Let's see...
1) You are correct, the weekly updates are all processed on Tuesday's. There is no option change the update on an individual basis, but, I am open to change the weekday.
2) Currently, it's cookie based, so even on simple logins a thread will be marked read after a certain time individual. I know, it's lame, and we are going to improve this with a forum upgrade which is due soon.
And no, as far as I understood, the threads will not be marked read upon receiving the subscription e-mail since it's really just cookie based.
Best,
Alex