I was using a single-jointed 3" loose ring snaffle (5" in the mouth). It was like the top one, here:
I do know that part (a LARGE part) of my problem is confidence. My first horse was drugged when I bought him. The first time I rode him at home, he threw me and tried to kill me- luckily I only broke 2 ribs. He was sold to me as a "kid friendly" horse. He went back the next day (very long story there...). I bought Ruby right away because I was afraid of being too scared to "get back on." I was VERY lucky that she was "the one" because I honestly had no idea what I was looking for. I want to go FAST on Ruby and she is more than willing, but I'm afraid of losing control, hence the search for the right bit. But more important than my confidence is her comfort. She has proven to me that she is a "take care of you" kind of horse. She's still a baby, but with every flick of her ear towards me, waiting for me to say "good girl," I know that she is tuned in to me. I have to remember that when I'm on her, though :) So, about the running- how do I get the confidence to hold on and let her go??
I think you both need to dial it back and work on walk and trot.. really work on getting a nice relaxed, forward walk.. then a nice relaxed forward trot.
Have you tried a jointed bit (french link, oval link, roller, etc.) with her? Or a happy mouth, or a myler?
"Strength is the ability to use a muscle without tension"