Looks like the vocal majority are willing to go to about 50 cards before making a switch to groups, so for this month (Round 7) we'll stick with the plan and it's "in once, in all".
I've half written a program that allows each person to specify their desired maximum number of cards. Just need to tidy it up a little and work out how to email each persons individual list from within MS-Access. We can have a poll over the next 3mths or so.
Thanks for your input.