That last point has to be the bane of your guys existence I believe.
Out of personal interest, wouldn't it be to conceivable to slack off more at pairing if you do it every four weeks anyway? People will piss in your carefully planned-out pairings-soup anyway the second they know wich low cost server to transfer to for easy kills, and will keep doing so until fresh gem transfers, excluding people who deleted all their characters, fresh accounts and anything in between, are barred from WvW for the remainder of the pairing.