^^ That is the style I'm planing on getting. I was going to try making my own, but it was a little daunting and I had the feeling that I would fail miserably.
Quick question to those experienced in bitless though - I'm going this version because it seems most similar to how I ride now (with a halter and reins). Would a sidepull/bosal etc still work in the same way? It seems to be the nose pressure that he reacts to, and doesn't the sidepull (I think it's the sidepull) work off poll pressure? I'm quite a 'newbie' to this.
For poll pressure, the reins connect to a continuous piece of leather that goes under the chin, up the cheek, over the poll, down the other cheek and under the chin again to the opposite side. It creates an 'X' shape under the horse's jaw, so that when you pull the rein, it not only creates pressure on the nose, but under the jaw and on top of the poll as well. This is a true bitless bridle, as most people understand it. I think that it is more often used by riders of English discipline, while the sidepull types are more often used by those of Western discipline.