I've got one, bought a Graflok conversion for my Anniversary Speed Graphic to be able to use it, and because the lens I calibrated the RF for doesn't have a shutter, I use it with the focal plane shutter.
Works very well with the infinity stops set back for the film offset -- I need to get/make a mask for my viewfinder and then this will be a top notch instant camera, with parts ranging from 1940-ish to 2021. A little bigger than a Polaroid 110, but I can still buy film, too...