I'm an antique myself, long a revolver, pistol and rifle man, but very (!) inexperienced with shotguns and specifically chokes.
My question would be: what is the difference, and why between so-called "clays" chokes and any other when the apparent dimensions (extended) and choke (full, extra full, etc) are the same. Or aren't they the same if the application is different? In this case clays vs turkey