OH here is another suggestion. When I have done the other swaps where you make 12 blocks all the same and then send to the moderator and she swaps them out with the other in the swap. We put them in the flat rate envelop and also include a flatrate envelop with the stamps on it addressed to ourselves and then the person in charge just has to put the 12 squares that are selected to be sent back and put them in your envelop and mail it back. I have done this many times and it all fits. Maybe that would work?????