My vet’s farrier cocktail is Dorm + Torb + Ace. For ones that are not lightweights, up to 1cc each, combined to be given IM.
One of mine gets anxious about the hinds due to a previous injury and jerks away but doesn’t want to be bad, so that makes him more anxious, but the tension makes it even harder to hold up the hinds. I’ve been able to wean him down now to 1/2cc of the Torb in the mix, and he is alert enough to be safe to hold a leg up, but mostly just snores through his appointment.
I would practice banging on the feet some. Though my younger horse can be a jerk about nailing the hinds sometimes unless he’s distracted with cookies, and I’ve done all manner of banging and hammering and clinching and whatnot (including sometimes to tighten a loose shoe) and he’s always been fine for me. I think he just doesn’t have much patience. It was the same trying to desensitize him to IV needles. Fine for me; jerk for the vet.