I have a RV-7 QB fuselage. The 7 bottom aft rivets on the top skin (F7106, dwg 28/43) are already installed on the fuselage longeron/side skin but need to be removed to accommodate the top skin (pre-punched). These are around the area of the wing bulkhead. Because of the canopy deck (also riveted on) a few of these look like they're going to be very difficult to set properly even with a very narrow bucking bar. Is there a pop rivet which would be acceptable here if need be?