Hi David...I know what you're doing!
When we do our panel work, we use Trempro/Vulkem (available from VTS) in the overlapping panel joints. Not sure if you are using bucked or Olympic rivets (assuming Olympics), but we also dip each one in Trempro before pulling them. It's a messy proposition, but it seals everything up real well.
Good luck - Moby will be as good as new before long ~