After putting this task off long enough, I decided to finally close up a fuel tank by installing its rear baffle. This has to be installed with tank sealant to ensure no leaks. Since this has to be done without access to the other side once complete, it must be done "in the blind" and without the ability to touch up any of the beads of sealant on the inside. Additionally, all of the rivets along the sealed areas need to ideally be driven while the sealant is still wet, so you're under a bit of a time pressure once you start.