The thing you have to remember with a horse with this issue, especially if there has been no right lead for a long period of time, is that there is very little muscle on the right side so they will want to pick up with the left naturally so you have to give them a little slack as they work on building the muscle tone on the right. The thing to remember is try not to get frustrated. It took me nearly a year to accomplish getting the right lead consistently without having to nag for it. Start small. At first, when you get a complete circle of right lead, reward them and end the lesson there. Hope I was able to help you a little. Wish you the best of luck! Dont get discouraged by this minor set back. (Sorry I had to send so many responses but apparently I wrote too much.) lol.
Once they figure out correct balance in the trot, bring them up into a controlled canter on the large circle (trust me, it will take a lot of work for that right lead!) if they dont pick up the right lead the first time, break down to a trot for a stride or two then pick back up and repeat until they do.Nose tipped in so you can see corner of the eye, hip pushed in, and use your outside leg. Once you do accomplish the right lead on the large circle, spiral into the smaller circle, just dont make it too small at first. You can also lope the entire arena and continue to ask for the right lead by breaking down and pushing back up with the nose in. Once you get a few strides on correct lead. Stop and walk to reward. (This took me nearly an hour to just get a few strides on the right a few times so it does take a while, thats why I say dont get frustrated. lol.)
Yes my mare is 21 and has been gaming with a club foot for the last 12 years and never once has slowed her down. As for the right lead, I feel your pain! I went through the same issue when I got my mare. She took a lot of hard work to get her to consistently pick it up as she is very stubborn. When I worked with a trainer for this problem, we did A LOT of exercises to the right. Do lots of circles around a cone. Our favorite exercise that made a world of difference for us was to start on a larger circle around the cone (start in the trot) and spiral in to a small circle and hold until they give you just a couple good strides of correct balance then let them spiral back out to the large circle as their reward.
I had posted a thread about barrel horses with a club foot, and a friend of yours suggested I talk to you, as you have a barrel horse with a club foot. Hopefully I have the right person! I was just looking for suggestions--my horse is 3 and is showing a slight right front club foot, and I am training him to do barrels right now. He is doing well except for not picking up his right lead very easily.