There is huge benefits to clicker training your horse. The whole principle is based in the science of behavior. It is going on already, whether you know it or not. So the more you know and understand the better you will be as a trainer, partner and communicator. You will be shocked by the difference in your horse. The mouthy pushiness only comes by people who are not aware of the behavior principles that govern the horses lives. It is super easy to get polite manners using food as a training tool. I have fixed horses of mouthiness and biting, even aggressive biters, using food as a reward. Again it is all in the basic education.
You can definitely add "clicker" training to what ever you are currently doing. You will see a big shift in your horses focus and enthusiasm. Whether you want to teach him to stand quietly, better transitions (upward or downward), clipping, trailer loading or jumping a course...or anything else in between.
Every horse does something to avoid something (traditional and Natural Horsemanship) or to get something (positive reinforcement) The key is something that the horse values. There is a huge tendency for humans to assign our own values and not really paying attention to the horses response. Because they are hard wired for food, due to survival, it's value as a motivator is unrivaled by anything we currently hold in horse training. Food, air, water, sleep and procreation are the other primary reinforcements fro which they are hard wired. As you move along in training you will find the food and clicker are not even a focus anymore. I could go on and on...I have used positive reinforcement for 28 years now. BYW the term clicker training is actually erroneous but has become a familiar term. At Sea World we didn't use clickers and we certainly didn't call it clicker training. I have been using it with horses for 18 years now and I have worked extensively with Beezie Madden, two time Olympic Gold medalist and she is on her way to London this year too. In fact I started my training business from an invitation from Beezie and her husband. I lived at their farm and worked with them and their horses. But I have also worked with Olympic coach and dressage rider, Jane Savoie as well as other international professionals.
Learning about positive reinforcement and how to apply it is easy and quite fun. If you want to learn more or watch some videos you can go to: On Target Training with Shawna Karrasch
OR Clicker Training for Horses - YouTube
Th"Clicker Trained Horse Remembers After 7 Years" is a fun one that everyone gets a kick out of. If you have more questions I will be happy to help.