I'm writing my own forum software (it's meant to be able to run with thousands of users on a cheapo vps- everything is as lightweight as I can pull it) and I ran into the same issue- if you want per-user posts/page settings, you can't grab shit by page, you gotta link by post, and then calculate the page. Extra calculations.
I'm still on the fence if it's gonna have per-user posts/page settings.