Hi Punchers, I am faced with a choice between a used Roper Whitney "No. 20" and a "No. 20-1" punch, but I am not aware of the difference between the two, and I am not in a position to physically compare them. Can anybody help? From Roper's current catalog I see they have a No 20 and a No 20 CTL, but no mention of this other variant called 20-1. Any advice? Many thanks!