I actually like the idea to buff the requirement to win per clan participant, this way people have to dedicate a bit into the game instead of grinding a day or two at the end.
To add something extra, we should add a point decay to the system, where you have to play a minimum of 1 clan war in order to avoid point decay (decay could be 10 points per day for example, though this is only a solution for early rushers).
Perhaps we should set up a registration button on the website where it would give a check at the begin of the month to participate in the monthly event (so we have active logs of who joins the "game of $$").