Join Date: Feb 2010
Location: Loudoun County, VA
I'm not an expert, nor did I have an OTTB, but I did have a horse that had a very high headset.
My trainer had me fix it by circling, sometimes very small, using inside rein to bend her to the inside. My circles got very very small, sometimes circling within a foot of my trainer on the inside. It took a couple of sessions, the circles getting bigger each time, but soon she was able to go at large in that headset.
It was a huge relief, her head was always straight up in the air before that!
Although another reason for his headset could be pain or a pinching saddle.
I hope this helps :) Good luck!