Don't have manual for the -M, but I do have a old version armorer's course PDF for the -L; -M specific features is not covered. As for using a set screw, as long as it has matching thread specs, I don't see why not. In fact, I recall reading someone doing just that with their -L some years ago. Other than starting with more pressure and then working your way down. I don't think there are any special break-in procedures aside from the usual (lube and shoot).