I am looking for information on the size of hole I need to make for the Ektar 20 3mm lens in an MPP lensboard (Mk7), the lens is as far as I undestand from the b loke in the shop (describing the items over the phone) is that the kodak ii in a prontor shutter and the Wray I asked about earlier is in a synchro-compour. Bt w what are the relative merits of these shutters - what are the actual speeds I know the max speeds but not those in between. Thanks.