I really feel your over thinking it. The cometec 1.78mm gasket is available from burton power and I wouldn’t like to bet money on the ford gasket being the extra 0.02mm and even if it was the differance in Cr is negligible.

But to answer your question, they have a top and bottom layer the middle layers are covered in a polymer and the whole lot is riveted loosely together. If you drill the rivets and add more middle layers it’s a case of bolting it back together square that shouldn’t be a problem due to the head locating dowles but I wouldn’t try to rivet it back together.

I’ve never heard of it being done but some one has to be the first.