Even if it is a "standard" size like 5x7 or 5x8, a modern holder will most likely not fit without adapting the back of the camera. The Rochester Universal is a fine early camera but so early that even in the smaller format, sizes for holders were not standard.
In many cases you take the holder you want to use, hold it up to the back of the camera and see what you have to do to make it work. Sometimes you remove wood from the holder opening and in some you add wood. Sometimes you also have to reset the "T distance" for the groundglass to match it up with your holder.