Right Angle Oil Filter Gasket Question

I am ready to attach my cast iron right angle oil filter adapter on my 1970 340 engine. My Felpro gasket kit includes the thin metallic gasket for under the bolt head, the thicker cork gasket for the inside of the bolt and what appears to be 2 of the large round gaskets that could be used for mounting the adapter to the engine block. One of the larger gaskets is thinner and more of a fiber material. The other is thicker. Does anybody know which gasket I need to use for my application?