I agree, the detail on things like this does slip out of the manual as we near the end. The door sills (like everything else) should get at least two coats of epoxy and then varnish or paint. I’d go through the whole clamping with Cello-o-fill assembly, let that cure, clean up any excess, fill any gaps and make sure all your edges are rounded the way you want them, then coat. Hope this helps!