This is a 6 year old post and I doubt your reply will reach the original posters. You could try and pm members directly, or make a new thread with pictures. Rotary points to the race and hook of the model and White made this type of machine with Rotary in the name from the 1890s and well into the 1950s. For Singer models there is an extensive list of serial number and year of production, I don't think anything equivalent has survived for White machines.