The whole world of back boots and the effect they can have on horses isn’t something I know much about! I’m lucky in that most of my horses haven’t really needed much help with this. One of my horses Atlantis is 13 this year and we still use young horse boots on him behind because his back end is so good!
I know different boots affect horses differently. I have an older horse, Unique who we sometimes change his back boots as he can be a bit lazier behind and if I’m trying to go fast in a class he can have a fence behind. For him we don’t use anything really strong it’s just a different feeling for him if we change the boots so he’s more aware of his back legs. At home we just jump him in normal boots.