Mamiya RB67 & Flash

Hi there, I was wondering if anyone out there has experience of using a
Mamiya RB67 with a Bowens Esprit 500 set up i.e. is it ok/safe to use the
synch from the Mamiya lens to one of the Bowens units? If so I take it that
the flash type should be set to "X" on the lens?

Any advice would be greatly appreciated.

Alan