It’s important to understand that a horse’s natural tendency is to resist pressure; therefore, it’s very important to begin teaching them to give to it instead – from any point they feel it on their body. Eventually they will move away from it with almost a whisper of a touch if a touch is needed at all. In a very sensitive horse, they can even learn to feel when your hand is near.
Even from the very beginning, a bit is an aid which is last in a chain of signals when a horse is being ridden. When trained to give to the slightest pressure, even a green horse will respond to leg pressure as if it is an old pro but, prior to that, since your body becomes a part of the horse’s balance wise, he will feel a shift in your weight the moment you even think of changing direction. THIS is the ultimate and primary guidance your horse will receive so far as direction. If that is ignored, he knows the bit is there. That said, I have not used a bit in fourty-one years.
However, since you will not actually be a part of your horse and, thus, lose that body guidance, you may need to use something which will indeed give you a little more control such as a mechanical hackamore. Gently used, they are kind.
If you do choose to go bitless, you will probably want to go over the very beginning steps of teaching your horse to give to even the slightest pressure just as if you are training a green horse. Next, see how he will do when being driven just with reins and a simple small-rope tied halter. Once he/she responds satisfactorily at that step, it is not even necessary to buy a new bridle. You can simply drop the noseband on an English bridle down and enclose it in the sidepieces where a bit would normally be held [Shorten the headpiece on both sides a little more than you would with a bit.] but always keep in mind that when being driven, your horse has lost the initial cues of body weight and leg pressure which are ultimately what guides a horse long before a bit is touched.