This is the only one I've ever seen. I have seen some other types for Kenmore and some for Slant-o-matic but the letters aren't as big. I'm thinking the key is to drop the feed dogs and to loosen the tension. Make sure thread flows real easy. About like you would adjust for FM.
I'm hoping someone knows how to use the Kenmore monogrammer. I have one but no instructions. Maybe someone has the instructions.