Update on Patching an Aluminum Skiff
I got so much good help on this site while trying to decide how to do this project, that I thought I'd pass on what's happening with it. I followed jratte's advice and wound up with West System's 860 Etch Kit. It provided cleaner, conditioner and a two part paste quite like Bondo. The whole repair from pounding the ding out to sanding the patch smooth took about twenty minutes work and two hours setting time. This stuff sets up quick, but it is also easy to work and pretty easy to sand. It can be used under water as well.
Also got the rear bench seat removed by just drilling out the rivets, so plan to go ahead with my original idea of putting a cockpit type seat spanning the two rear benches and a casting deck in the bow.