Good, so you've already discovered how smart they are and what a good work ethic they have. Sounds like he likes having a job and good guidance from his rider. As for the right lead, what I did was strengthen his left hind leg by riding shoulder-fore and haunches-in at the walk to get him to put that leg more under his center of gravity. Once he could do it easily, and I was convinced it was pulling more weight, I would canter on very large circles and never straightaways. The circles help them find their balance and keep it. The circle also usually prevent cross-firing, but not always. Hope that helps. TB are great!
You just have to see your distance...you don't have to like it.