Yeah you have to rotate your players regularly siince they dont play games everyday.. but as I said before theres no reason you cant set your roster for the whole week ahead and then just keep an eye out for injuries.
It's pretty rare to have all 10 positions filled more than a couple times a week so theres not much to think about really.. just start anyone who's playing that night.
As far as scoring, it's like a win/loss record for each stat category... so every morning you'll see the current record against your opponent, and then on Monday the final accumulative score for that week will be reflected in the overall league score table. Basically you can get a potential 12 wins every week because there are 12 stat categories.
So a bit like the football, it's not how good your team is but how good it is compared to the team you are playing against that week, which I think makes it a bit more interesting than just a standard points league.