I don't have a reference that I can give. All the 'experienced' instructors and organisations I've flown for have required a signoff to operate PIC from the RHS and for a note/signoff (similar to those used for GPS enroute navigation etc) in the logbook. Basically, it involves demonstrating that you can do all the emergency procedures from the RHS.
No requirements whatsoever apart from the PIC ensuring that a qualified person is strapped into a command seat and the usual requirement that the PIC ensure that the operation is safe.
I reckon it takes about 30 seconds to get used to the RHS in a light piston single or twin.
No reference = no restrictions.
FRQ CB