<p>Dave, welcome back to film<br>
I do not use Hassy equipment but you may get some answers from the Zeiss Historical lenses home page.<a href="http://www.zeiss.com/camera-lenses/en_us/camera_lenses/classics/hasselblad.html">Hasselblad | ZEISS United States</a><br>
Years ago i sold a Minolta Spotmeter f and that was a mistake. The one degree can really tag the correct exposure. Lastly, there have to be some used books out there on Close-up Hassy photography. Check out Bookfinder. Good luck<br>
Ed</p>