You can try it with her while walking beside her on the ground and simulating rein cues to get an idea of how she will react.
My mare has always been prancey with snaffles. What seems to be working with her is A) let her prance sometimes, and B) switching her to a curb bit. When she just has extra energy, I let her prance away. If it gets too annoying, or if she is doing "I'm nervous" prancing, then I bring her to a stop. And this is part of her ongoing "Nothing is better than stopping" practice - using stops as rewards, and insisting on perfect stops every time.
When nervous-scared with a snaffle, she'll fight and never learn that it is OK to relax. With the curb, she is learning to stand still...and then when nothing bad happens, she starts to learn that she didn't need to be nervous to begin with.
My 3 horses have different bits. Our gelding is a snaffle kind of guy, but my mare is calmer with the curb. Mia liked a Waterborn better than a normal snaffle, although some folks say that is harsher. She also prefers one joint snaffles to french links.
Since you already have the bit, why not try her out with it on the ground and see how she reacts? If she doesn't respond well, ditch it. BTW - I don't show, compete in anything, have vast experience or train anyone in anything, so take my comments with a big steaming cup of FWIW!