There is no one answer to this. It depends on the variables of the material you're using and the features and build of your machine. Before you start sewing for real, experiment with the fabric and see how it handles. Given the scale of 1/6, I usually like feet that give me the most visibility. My fave is the clear open toed one. I also use magnifiers and extra light to better position things as there is so little allowance. There are tricks you can use like using lead fabric or tape to get a straight line going or so the little bit of 1/6 fabric doesn't get eaten by the feed dog. Lots of trial and error.