Natural and weighted bell boots don’t go together . The only way you can enhance you horse’s gaits NATURALLY is to ride them and train them how to correctly use themselves.
Lots of strong reactions happens when you ask about training gimmicks/aids, and heaven forbid you try to imitate saddleseat! I rode at an ASB barn and the tools aren’t evil, and I personally wondered if it was how Totilas got his action. BUT, I’m in the camp that didn’t like that toe flicking trend and very much encourage you to explore Dr. Heuschmann’s work about leg movers vs. back movers. If you want a back mover, I don’t think weighting the legs will help.
I think that from your original post you are missing the whole concept of “dressage” training. Our aim is to improve the horse’s strength and ability through appropriate gymnastic exercises, suitable for each horse at his particular stage of physical capabilities. We aren’t looking for artificial gaits.
Collection comes from the engagement of muscles in the hind end.