Greetings. I have an aluminum sailboat mast, 6160-T6, 3/16 wall, oval extrusion 10x7”. There are numerous 1/8” old rivet holes and a few 1/4” holes. There are 6, slots which are 1” x 3” round at both ends. In the corners, 4 old rivet holes which held a halyard exit plate now removed. My thinking is ...