Just wanted to add that the intake is an aluminum 6 Pack manifold.
I was more concerned about sucking oil from the valley into the intakes if I don't seal well on the ports.
I called Cometic about thicker gaskets. They have a 0.060 like Felpro, the next size up is 0.094 thick. Nothing in between. You have to pick a thickness from their stock of materials.
I made the shims from an old Felpro 0.054 head gasket.
I measured a new Felpro MS 90109 gasket. Measures 0.054 / 0.059 across the raised sealing beads. I don't know the prior history on these heads, but the machine shop said the deck side had been resurfaced before. They didn't say anything about the intake side being resurfaced.
The used Felpro gasket measures 0.039 / 0.047
