On the subject of submission length, I tend to think of it as the aggregate of the weekly submissions. If 5 people all posted 6.5k words, I must admit I would be a bit irked, because that would be 32.5k words instead of 25k, plus 30%! It doesn't sound like a lot, but my writing time is heavily limited by work, so I get a bit jealous of it when it comes to critiquing.
This is sounding like sour grapes, it's not supposed to. I'm content to read 6.6k from you - not a problem for me. I've been over 5k myself, a bit. (But not over 6k, Marci, lol).
I like the sound of the format you describe, certainly an easier way to digest a longer submission, and to get a better overall flavour for the piece.