If the cylinder head is aluminium alloy, beware of using copper gaskets!
In the presence of any moisture, (as in storage ) which will probably produce an electrolyte, the Aluminium alloy will be corroded by the copper.
Gasket cements may not withstand the temperature when the engine is working hard.
This does happen! I have seen alloy, "water" cooled exhaust manifolds and gearbox oil coolers, on marine engines ruined by the use of copper gaskets.
It would be preferable to use a steel faced gasket, if the head is light alloy.
Copper between a steel spacer and the steel exhaust flange will be quite acceptable.
You might get away with using a copper gasket, with a steel shim between the Aluminium and the alloy head. In this way you remove the Copper/Aluminium electrolytic cell.
Howard