The ultra copper is a gasket substitute. Clean the surfaces then apply a thincoat to one side. Let it dry for 10min or so and then bolt together. Once completely dry it creates a barrier to stop leaks. On the bolts, add a dab and then screw them in and let dry! I use the ultra copper on most of my screws/bolts where I really dont want them to come loose(instead of locktite!).

Oh, and I remeasured the bolts. 5mm by 5/8".