I finally learned to halt properly by applying what I learned in Udo Burger’s book “The Way to Perfect Horsemanship”.
According to Burger the horse cannot react to a halting aid when a hind leg is pushing the horse forward.
So I changed my halt signal to alternating hands, when one side of my seat sinks down the horse’s hind leg on that side is in the air, I twitch that rein and alternate it with the other rein when my other seat bone sinks down.
Another thing I learned from Burger is how to use my leg for collection, I apply my leg as the hind leg on that side is hitting the ground (the horse’s barrel is pushing my leg away and my seat on that side is rising.)
I tried both these aids (one side hand and the other side my lower leg) on my first horse, who I’d been riding for decades. Instant halt and he went into ramener for the first time in his life.
I then tried it on an Arab mare, green broke maybe with 3 months of riding, who did not understand halting aids besides WHOA. She stopped immediately with just the hand aids.
When I started riding again the first ride at a local hunt seat stable I was riding her horse around the ring and did my new halt–instant obedience and the riding teacher yelled out “what did you do?” Apparently that mare was reluctant to stop and her owner had never seen a better halt on her.
Since I am not into dressage riding I sort of dropped using the “collecting” leg and now I just alternate the reins.
I am just riding lesson horses now. Once the horses figure out what I am “saying” I often get easy, prompt, well balanced halts. Of course if I use both hand and leg the result is better (“square halt”) but I often forget all about my leg. The horses still halt for me once they figure out that I am not a normal lesson rider and my aids actually mean something.
I had been trying to figure out the proper timing of my aids for a long time. Reading Udo Burger’s book made it all perfectly clear and the horses I ride really appreciate it.