I have a Toho FC-45X view camera.
Because I was having trouble doing architectural photography in tight quarters, even with a 90 mm lens, I got myself a 75 mm lens. I also decided to splurge and get the Toho eccentric lens board with it. As Kerry Thalmann has noted, it is a neat device. It functions as a lens board, and you can just leave the lens centered in it and use it that way, but it does extend possible shifts significantly. Be that as it may, I discovered that it was not actually that useful for my 75 mm lens. That lens has an image circle of 195 mm, and because of light fall off and other problems that seem endemic to wide angle lenses, one has to be careful about large shifts. It seems impractical to use much more that 15-20 mm in most cases, and that can be accomodated by the Toho's normal movements, even at 80 mm from the lens, which is the rear flange distance for the lens. My 90 mm lens, on the other hand, has a very large image circle, but I was finding that a knob would hit the bellows with large vertical shifts. That together with bellows stiffness prevented my making full use of the 90 mm lens's image circle So I've mounted that lens in the eccentric lens board and I expect it will solve some of my problems using the lens. I put the 75 mm lens in a standard lens board, and it seems to function well there. All told, I am glad I got the eccentric lens board, but it turned out it is not very useful for what I intended. For focal lengths even shorter than 75 mm, I suspect the problem would be even worse.
I wonder if the same quandary arises in using a bag bellows. Short focal length lenses tend to have quite small image circles, and so the potential movements possible with a bag bellows may not be particularly useful. Perhaps such measures are more useful for moderately short, but not very short focal lengths.