I worked with 4 or 5 of these in my career. Most of them have been scrapped; sometimes people salvage the lenses for ULF work. I suspect most of us who try to adapt these for field work give up...
The shutter is usually a two leaf behind the lens activated by a solenoid. As the time is usually several seconds to a minute there is no need for fractional second timing. The focal length should be half the distance to the film when the scale is set at 100%. Those flat field copy lenses can capture really good detail with pretty decent contrast which is why people liked trying them out for ULF landscapes.