I drill a the same size as the screw but don't see why a 32nd of an inch smaller would not work. The problem with drilling and using a self tapping screw on a re installation is you would have to weld up the existing holes.
My last hull was painted and a older model that did have minor corrosion around the holes but not anything bad. Haven't had to change it on my new one but it won't be long. I spend 95% of my airboat time in salt water.
