Last month, I did the same thing, setting up my postcard factory on a bed in Cusco and cranking out 8 one evening. Although, now I use the pre-cut watercolour postcards and add some colour.
It's especially fun to think of old friends receiving them and remarking, "where is crazy John now?".
But here's the caution 5 weeks after posting them, not one has arrived in Canada. On investigating, it seems that a service is stalled indefinitely because of a labour dispute in Peru. You'd think they would have told me when I bought the stamps, wouldn't you.