Welcome. One will not be enough....Plus there are all those additional lenses out there beckoning you :-)

The flash sync being araldited into the X position may be so as to protect the self-timer (someone please correct me if I'm wrong with the Mamiya). On some cameras, such as the Yashica TLRs, if you put the flash sync on M then tried to use the self timer, you rogered the shutter.

Paul