Personally, I have massive abundances of free time on my hands, and I'm able to easily read pretty much any posts. So for me, limited time isn't much of an issue. However, I think that it might be that we who have lots of time could place a little 'post summary' in the ooc or something of the like, to help you guys keep up.

I think creating a rules system like you're doing is a bit overboard, and I think people might ignore that just because they dislike someone trying to tell them what to do, as is a common reaction to such systems. I think it'd be best just to ask people to try and help out those with smaller quantities of free time at their disposal.