Took a private lesson on Saturday with Gayle. We are working on cantering without her dragging me all over the place or just stopping. At Gayle's suggestion, we tried a dressage saddle, a milder bit, and a different girth... somehow the lesson was a whole lot better. Dreamer responded well to me, I felt much more comfortable in that saddle and my body was able to do what Gayle directed me to do.
With all the different variables we added to this lesson, I can't pinpoint exactly what created the more positive outcome, but now I have ordered all new tack for Dreamer just to cover everything.