Hello! I'm new here, but I instantly gravitated to this post. Firstly, don't worry about how much time it takes... the quality of the experience is so important because you want to build her trust in you. Now, my two cents. When a horse's head or feet are messed with or restrained in anyway, it can be very frightening to them, and so they are very protective of these areas. I like the idea of of think low... yes, the lower part of the neck is good, and slowly work your way up to her throatlatch, approach and retreat, then under her chin and on her jaw bone (horses seem to be okay with the jaw area). Most importantly, convey positive thoughts to her- you want her to think that this new exercise is very special indeed- she will feel this energy, even though she may not agree with it in the beginning. When you can rub her head with your hands (do not restrain it in any way) then put some rope in your hand and use it to groom her, slowly releasing it and rubbing it on her head. Then slowly make loops with it and loop it gently over her poll area (no pressure, please!) and just rub it and then release it, same thing with her muzzle, create a large loop and then put it over her muzzle and then just rub her with it. This could take days or even weeks... just take your time. Then when she's comfortable with being rubbed everywhere with a rope and the feel of loops on her head- introduce the halter to her. Make it very enjoyable for her- let her think that she's at the spa!