I think I better pipe in here to save the confusion.
At the end of May when sign up closes I will try to randomly break up all the participants into groups that do not exceed 12. We have not yet had this many in a group if I recall correctly. More than this number and we are pushing to be able to get the prints and some protecting bag &/or card/s into the prepaid envelopes available from the post office.
Currently with 13 participants I am thinking of two groups, one with 6 and one with 7. Everyone only needs to send in one print less than the number in the group as you don't need one for yourself. If you want to send one to the organiser please make this clear as I return the extras.
The numbers in the two groups could change if we have more people sign up before the end of this month
Hope this helps.