focus is critical on a sliding back. best to shoot wide open and make sure the ground glass and back are perfectly aligned. my flex adapter(p1) is not perfect, like most, and i need to change focus by a few mm to get perfect focus.
while i do reccomend the newer digital lenses, rodenstock has a 105mm, digital for about a grand. very nice.. also later, more modern lenses, esp those marked APO do well (atleast with the older backs, P25).
you will need a cable to sync the lens and back together most likely. its kindof a mess of wires. you usually have to wake the back up with one shutter press on one release then trip the shutter release to make an exposure. connect any strobes to the back itself. there is the one shot cable by kapture group that takes just one press to wake and shoot, it runs 400 tho. nice for a plate camera, like a cambo wide ds, alpa or similiar but the other way really isnt that bad.