Working out the "hinky" in the canter

The Spotted Wonder is at times a royal piece of work.   Though I've bettered her behavior since we began a couple of years ago she will still reliably pull a few stunts.  Independent changes of direction, refusals, bolting/bucking when asked for a canter.   Now none of these are an all the time thing, and she is fairly predictable, but the canter transition thing scares the heck out of me because it goes like this...you pick up the canter and it is good, suddenly she kicks it up about five notches (I'm talking in a split second), grabs the bit, and she is off.  If you make contact after that point she is going to twist herself up into a buck.   So you can take your chances at the buck, at her top speed..........or ride it out.    On the bright side, if you are pointed away from home it NEVER happens, if I am away from home it NEVER happens.   So it is all involved in her head with the original barn sour issue she came here with.  She also is not strong at the hand gallop, so she is gonna run out of steam if you are too far from home.  But the whole scenario can be dangerous to my long-term well being.  So I'm working hard at getting the hinky out of the canter and develop a strong canter vs. the next gear hand gallop ummm run-away thing.   The downside of course is I'm building a horse that can run longer if she does pull a stunt.   We are working on shorter, but faster rides, and I'm trying to overcome my fears of what might go wrong on these solo rides.  The good end of this is she is reliably cantering a quarter of a mile (I know wooooo weee not very far yet but beats the five or six strides she used to do) and so far hasn't spooked, spun back, or otherwise caused an unplanned dismount.  She did surprisingly well on the flat woodland trail that opens up onto a grassy trail last night.  Picked up a nice rhythmic canter as soon as we stepped off the hill trail, gathered up a bit of speed, then settled in with just minimal encouragement.  Her trot was going well last night  on the flat at a solid 8-9 mph.   We have but a few weeks to get ready for the next one, so not sure that anything I'm doing will help all that much, but maybe by FALL we can see some better times  (or at least better recoveries) by adding a new gear to the flats and hills to enhance the cardio work.

 Based on her first loop at Indy we should be able to hang with  perhaps a moderate LD once we are out of the heat and humidity.  In the heat though...it will be slow going.