I would use stainless wire, as CNC inferred. Shoot for about .006" stick-out on the deck. I would spray the gasket with Permatex HI-Tack areosol spray gasket sealer. I would also expect to get some seepage anyway, which matters little on the track, but makes it imperative that you drain the block between races to avoid water in the cylinders. That is why I went away from copper.
That, and the fact that a copper head gasket will work harden over time, making it necessary to re-anneal the gasket in an oven or BBQ grill.
