In my opinion it is much better practice to put a groove in the camera back rather than attempt to alter holders. For one thing, you make one change on the back, and that is it. If you mess with the holders you have to alter them twice for however many you have.
The F&S is a great old camera but very much an odd-ball with regard to the rib on the camera back and the groove on the holders. The only reason to stay with the original configuration, IMO, is if you already have three or four F&S holders and simply want to add one or two more.
Otherwise, just change the back. I am surprised how many people feel that this is somehow mutilating the camera. In fact, most F&S cameras that I have seen have already been so altered because F&S holders are very rare.
The only time I would recommend not doing this would be in the case of a camera in Mint+ condition that would have more collectible than user value. I actually had a Korona like that at one time, and sold it because I did not want to use it and destroy the value. But very few banquet cameras are in that kind of condition.