I remember a women rewiring a 201 for free motion embroidery. She did it with out a hoop and was quite experienced. She went from a modern machine to an old cast iron model with black japanning, because she had taken a liking to them and thought about it for some time. She mostly worked with tension to begin with and reported back she had adopted to her "new" machine. I don't think she used any special tutorials or embroidery groups for it. I remember she found a new open toe foot she liked, but she had more than one. A 201 isn't an obvious choice for FME, it's often model 15 like your 15-91. There are some fantastic videos on older 15 treadles to be watched. I have never been able to do anything like JudyTheSewer, I'm very impressed by the neat stitching.