I'm a little confused about the size of the rulers. I'm trying to purchase the Mastery Kit ($199 for all the rulers) but there appear to be two options, one for (LOW SHANK ONLY), and another that doesn't say anything about the shank. What is the difference? Can you tell me which of these options will work with my Viking Designer I machine? Also, what if I get a new machine (considering a Janome), will the rulers work with any of the Janome machines? Thanks!