I've organised a few of those coop levels before, and I'd say you REALLY need to design the larger flow before starting on the level. You can add the smaller platforms later but if you skip flow you'll end up with levels that do not make much sense, because some people add the weirdest stuff.

Wether to have another LMAT would depend on participation (I'm saying this even though I haven't done much for this one).. maybe you would get more participation after a one month break.