Finding the right bit

[APKBUICU@aol.com]

Hello all:
I recently purchased an Arabian mare who has had a short racetrack career. 
She tends to hold her head quite high and I am having some difficulty finding 
the right bit for her. I tried a Mylar level two snaffle with a short shank 
and she did well except that it was to wide. I then tried a 4-3/4" 
Kimberwicke and she hates it. She is soft in the mouth and does not need a 
bit that will stop her, she just needs something that will allow her to round 
her back and begin to use her hind end. She is  6 years old, under saddle for 
a year last October, 6 months walk/trot on the trail and 6 months track 
training. Any help would be appreciated! Thanks