I received the replacement fitting and nut for the return line to replace the one I cross-threaded a couple of days ago. I cleaned all the parts, installed the fitting to the cover, and sealed the cover to the tank rib. As I did on the left tank, I used torx plus screws to secure the cover to the rib, hopefully being easier to remove that phillips screws should the need arrive. Once the sealant cures, the tank will be ready for testing.
All parts cleaned and ready for installation.
Return line fitting installed, and sealant applied to cover and rib.