For CTRs, like you want to do, my instincts say that an english saddle might be better for him, (are we talking about Harley?) because it's much lighter than a western saddle. You'll also want to get an english saddle pad for him too.
Yeah, I think a light weight saddle would be nice, especially since my western is not fitting him well. I used my saddle to do CTR's for 5 years with Belle and she never had a sore back, so it was one of those things, if it's not broke don't fix it. But it's "broke" now:), not litereally, but it's not working on Harley. I've always said if I ever had to get a different saddle, I'd want something more lightweight. I never thought I'd want an English tho:), But I'd sure like to try one.
Becky