ok this is for Lynn... I picked up the rivet gun tonight from Bill.... it is a 4x goose neck gun which should be up to the task... i have set rivets with a smaller gun but struggled... this thing although small weighs a fair bit...
the snaps are readily available... i have worked out that a 5/8 brazier / truss / liverpool head snap is the way to go... based on the theory that the rivet head when formed is just shy of 16mm diameter.