Received Gretz pitot tube bracket and started the installation. Had to drill out several rivets on main spar and No.3 three rib. Used several spacers per installation instructions to level the bracket with the bottom of the wing. Part of the bracket supports needed to be filed to allow the bracket to pass through it. Located and cut hole in bottom skin for the bracket. Ran out of grinding pads and will have to finish it later.
Note: This would have been easier if I had decided on the type of pitot I would use before I riveted the bottom skin to the skeleton.