Thanks for all this. I need to spend some time parsing it.
One thing that CohortMe is doing that keeps the thing from being unwieldy is that I only go back 12 periods. So only 12 weeks, or 12 days or 12 months.
Not a perfect solution, but it's version 0.0.1 :) I really only wanted to see 12 weeks right now anyways. Until I have some decent data going into the months.