Best Neck Training Harness for Bodybuilding and Combat Sports

I am looking to build a thicker neck for both aesthetic reasons and for my combat sports training. I am looking for the best neck training harness that is comfortable and can handle some decent weight. I have seen the ones from IronMind and some cheaper options on Amazon.

I am worried about the straps digging into my head or the chain being too short. I want something that I can use for both extensions and curls. I am training in Vancouver and I want to make sure I am doing this safely so I do not end up with a neck injury.

What are your experiences with neck harnesses? Do you find that they actually make a difference in your overall physique? I have heard that a thick neck is a sign of a truly powerful lifter. If you have a specific routine for neck training please share it with me.