Hurray, Clyde did it!! Yesterday, he took the cue to canter correctly on his left lead after the 2nd attempt. I think the exercises and shifting our weight to the outside is perhaps working/paying off. Hope it continutes. . .
Thanks so much for your responses, will definitely try lunging and turn of the forehand (this will be a learning experience for both of us, lol).
As for jumping, he just loves it and really perks right up, just like cantering. For now, however, we are trotting him over low cross rails to help him learn to balance up better and to keep him under control. When we first started, he would only canter the jumps and when asked to trot over them would paddle over them (he would change his lead in the middle of the jump, his front leg would hook around the jump bringing it down and he would then stumble). He no longer paddles now and only very occasionally hesitates slightly when jumping to figure out his footing.
Nynx, thank you so much for your concern, it is appreciated. Most definitely yes allowing a horse to continue cantering whenever he feels like it is dangerous. Please rest assured that he is checked and not allowed to continue whenever he does this. I only mentioned here to emphasize the fact that Clyde does pick up canter on the left lead.
He is such a happy and fun horse to ride, I can't believe nobody else wants to ride him! Also, he is so very tolerant of our poor attempts to bring him back into condition

. We just want to keep him healthy and happy by bringing him along gradually for great long-term results.