Im having trouble with my new horse?

I got a new horse about 9 months ago now, he came from a very run down place and has been used as a roping horse in the rodeos. i have been around horses my whole life and i no a lot about them i have two other horses that i event at open level and i am wanting to get Ru to this level as he has an amazing jumping ability, however he does pose a few problems in dressage that i need help with! because he has been used as a roping horse he likes to turn very quickly i have broken him out of this habit in both walk and trot however in the canter when i am doing a big twenty meter circle his body is constantly tilted in with his legs out the other side as if he going around barrels (only he stays on the outside of the circle and does it). another problem i have with him is getting him to canter and the correct leg when on the left rein. he has adapted very well to my leg aids for canter (inside leg on the girth outside leg behind the girth) when on the right rein but when i get him on the left rein he counter canters. i no its not his fault because the people who use to have him never corrected him when he cantered on the wrong leg but it is a major issue if i want to persist and get him up to scratch. i do believe he is worth persisting with because he jumps absolutely anything and everything with such a big scope, but these problems in dressage are restricting me. any ideas ?