Prosealed then riveted the tank attach Z brackets on rear baffle of left fuel tank. I used the 42H closed end pull rivets called out in plans for Z attatch. I used the 41H rivets for the holes adjacent to the Z brackets which hold baffle to rear rib flanges directly.
These were pretty easy to install. I spun the rivet in proseal and twisted it as it lowed into open hole. This helps seal the hole and no external sealant required.