there are about 3 or 4 base gasket thicknesses
I bought a whole collection before my rebuild hoping to adjust the squish slightly, but then discovered a slight lip at the top of my cylinder so decided to keep the base the same thickness to avoid contact with the lip
I only use a bit of grease on the gaskets that may need to be opened from time to time, eg water pump, clutch and rhs engine cover, this is just to stop them sticking and tearing (very common around the water parts.
OH and i use a fairly generous amount of grease to keep the o-rings in place on the cylinder head