What lathe do you have? This is a 14" Rockwell metal lathe. You managed to watch the video before I named it lol. I doubt your using your rest wrong. If you can turn long skinny parts with no chatter then must be correct. Different manufacturers or models picked different sides I guess. I too thought it would crash mounting the scale on the left but in my case most of the time it wont. My chuck is a bit large 10". If I had a 9" chuck the saddle would go under the chuck and not hit, as long as the jaws were not extended beyond the chuck diameter. Anytime you extend the chuck jaws beyond the chuck you should really look things over. A lot of Cnc lathes tell you "Do not extend chuck jaws beyond the chuck." Most cases there saying that because it will rip the tool setter off and it makes a hydrologic or air chuck have less chucking force at high rpm. At least when od chucking. I'd chucking it would grip more better.