I have been using equine chiropractors for 15 years and it has made a notable difference.
My chiropractors have always used their hands only.
Aside from periodic treatments on the Arab for an injured vertebra that happened before I rescued him, the most notable treatment was on my then 3 yo Tennessee Walker.
All of a sudden Sultan could not hold his running walk for more than 50 or so feet without breaking into a trot.
My chiropractorl/DVM discovered that the playful young lad had managed to put his Atlas bone (head/neck area) and his sacrum (butt) both of out place. No doubt in the pasture because he was a fractious young man and loved to devil the alpha-dominant horse whenever he thought he could get away with it
She adjusted him with instructions to give him a week off. Ended up I gave him two weeks off. When I did ride him again he was a gaitin' fool with a beautiful classic head bob that Walkers have.
So my vote is for the chiropractor as long as they are qualified and can provide references