Thanks for this information. I hope that I can put things back together just as you did. I would like to put back the aluminum rivets since they won't be a dissimilar metal and cannot unscrew with use.
I am finding out by the way that oversized aluminum rivets of 17/64 and 9/32" are available for aircraft repairs where a rivet has been removed and the hole has been enlarged. There are special rivet removal tools that center on the head of the rivet to insure that the drilled hole is centered that I am considering. I have not used one. Drilling just deep enough to remove the head and tapping out the rest of the rivet might be something I will try to do to prevent enlarging the hole as well. I have not had time to fully research whether the oversized aircraft rivets would be suitable for the Marine application with regards to alloy etc. But wanted to mention this in case it is helpful to someone with oversized holes.