I would have to guess that most macro work with film cameras is done with 35mm equipment. There were systems like the Nikon Multiphot and the Polaroid MP-4 which allowed macro work to be done with more convenience on 4X5 film but this was often copy work. If you are limited to a magnification of not greater than 1:1, any subject which is 24X36mm or smaller should probably be done with 35mm equipment. With a rigid set-up and fine grain film you can enlarge the 35mm slide or negative quite a lot. A subject which is 24X36mm and which is shot at 1:1 will provide the same usable space on the slide or negative on 35mm film as on the film of any larger format. To gain any advantage in image quality by using medium format equipment you would need to shoot the same subject at 2X or 3X. This is much more difficult to do with medium format equipment. I have plenty of 35mm macro equipment but my medium format SLR cameras are all Bronica ETR/SQ/GS-1 models and the bodies have no shutters. If I had a Pentax 6X7 I might make my own extension tubes in different lengths and attach enlarging lenses to them. This would work on a coy stand or with a strong focusing rail.