Use solid copper for all models. For a low performance, mildly tuned A10 you can use composite gaskets (usually copper/asbestos) if thats all you have, but you're much better off using the gasket as a pattern and cutting one out of copper sheet (1mm is about ideal). The early semi-unit A10s had skimpier finning and a thinner flange on the base of the cylinder barrels, but I'm pretty sure the head gaskets are the same pattern.
Just remember if you use solid copper you must anneal it first (heat to cherry-red then quench immediately in a bucket of water). This isn't necessary for composties.
