Just a note that I had the details on the back of my card wrong, I checked my notes (when I could find them...) and it was ID-11 stock (not 1+1), for 14 minutes. I'll check my P.O. Box again today and report back...
My housemates are getting a kick out of it too, I leave them on the coffee table for people to have a look at. Comments from non-photographers are often quite insightful, but so far the best have been "How much do you think it cost them to have these printed?" and "do you think they paid someone to stand there so they could take that?" (clamming at sunset).