So first off I have an older mare who is a pretty difficult mare to do somethings with. All her siblings follow this. They're all hot and like to do what they want to do. So with that being said its hard to do somethings cause she wants to fight you and get her way till she realizes she's not going to win. So my first thing is, She is very hard mouthed and I want to get her softer. She is older so I don't know how easy that will be. But what kind of bit specifically would you use. I'm thinking a snaffle but I would like another opionion on that. I run her in a million dollar bit with the rope band usually or sometimes go to a twisted dog bone. 

She is one that can run a beautiful patteren and run a low 17 on a standard then the next weekend completley blow the first barrel. It is always just the first barrel. She has been vetted, saddle checked, I treat her like a queen, so supplements and chiro, you name it I did it. But she does get very stiff before I run her so whats something I could to do keep her loose. I do keep her going in circles before. She can walk up and down the alley no problem all day. But when its time to run its a big fight. She doesn't just blow the first barrel when shes tough to get in but also when she is easy to get in. I take her to do time onlys at a very slow pace and don't push for speed. To teach her that we aren't going to run everytime and that she can relax. Things can be going great for four weeks at a slow speed and slowly work my way back up and runs great then back to where I started. I wouldn't try so hard to fix her if she couldn't run. But this mare can win races by .4 tenths if not more and win rodeos and be super awesome. I just need new in sight. I probably already tried a lot of things. But she is one that likes to have things her way. Shes a super super stubborn mare. But one of the best ones I have ever had as well. 

She doesn't have ulcers, she doesn't have any problems soudness wise. What about the oils and cbd stuff to calm her? I do already use th oxygen relax paste. It was helping at first. 

How old is she?  You say older but older can mean completely different ages to different people. 

18. She hasn't been run a ton. She had years where she sat and years where she was just a every now and then kind of horse. I have tested her limits probably

In my non-professional experience I have found that once a horse knows the pattern that they need to not see or work the pattern at any speed, like lope and above.  

I wholly changed my stallion's first barrel at a walk and trot. I learned to be a lefty with the rocket mare at a walk and trot. Both horses are completely different temperments but neither would have stayed sane working the pattern with any three beat gait with as many repetitions as it takes to learn something new.

I use a walked pattern for every horse to show we are done working, and unless they do something bonehead it is the end of the workout. If they do something bonehead, which you can tell as easily at a walk or trot, we repeat at the slow speed until they are soft and listening.