RB67 question for the old timers.
I can't answer your question, but you might try here: http://photo.net/bboard/q-and-a?topic_id=35&category=Mamiya+RB%2fRZ
It's a fairly active forum of Mamiya RB and RZ users, as active as any I know of, at any rate. They might know an answer to your question.
|Chicago Alley by tko|
from Down the alleyway
|Callan-5680 by vbuhay|
from What Child's Dream May Come
|Widget by Wilfried HKG|
|Oxbow Bend by stickpointed|
from Landscape - Colour #2