Finished attaching small brackets to assy w/ my Numatex squeezer...which works perfect. The upside down riveting did not go very well, Thought I was doing a good job but noticed I smashed a number of heads. Drilled out six rivets and reworked. �? ! I finally realized what was casing the difficulty...the spar is flexing up and down when I put pressure to rivet. Once I realized what the issue was I corrected all remaining rivets.