I have a 5yr old futurity mare, she's a pretty strong free runner. I have been running her lately in a Johnson Hack, at the last rodeo I had more problems getting her to come back a bit and rate. My question is what bit should I go to next? She does well in chain mouthpieces. I can ride her at home and have been working on getting her to stop at rate doing slow work usually in snaffle just seems when we go to make a run she gets strong.