Commando Cylinder Head Gaskets 273 1967

Hi, Is there anyone, that provides really thin metallic cylinder-head gaskets that will fit exactly the 273 diameter will not have any influence to the commando-compression 10.5:1?

Most of the gaskets found on the web fit every diameter from 273 to 340.

Or doesn't it matter at all what gasket to put on?

Thanks, Robert