I love how you have all those versatile pieces :) Now uhhh, some of these questions may seem stupid. I have been wanting to switch to bitless for a while now, but every trainer I have ever had is set on training bridle horses for arena riding only, etc. The opposite of me. First of all, what is a sidepull/sidepull noseband? I am an english rider but I my horse is going to be english AND western. Also, what is the chin strap supposed to be? Like a curb chain? Also, you have a one ear headstall and a split ear headstall. What is the point of the difference? Also, what would you recommend for a horse that is young and needs lots of control, but is also gentle and versatile?
Thank you! And no, they don't seem stupid :) I work with tack, so I hear just about every question and comment and get to learn a lot by what different people ask. For example, I just made someone a hanger for their bosal today and they wanted a gullet strap. I took their bosal apart, including a leather loop they'd tied onto the bottom of the bosal that I assumed was for attaching a lead rope. I thought this was an interesting request since bosals don't typically have gullet straps and you lead with the mecate, not a lead rope. Turns out, when I returned it today, the strap was a makeshift gullet strap that she didn't need since I built one in, and she wanted a gullet strap because, when she was leading her horse, the bosal would sometimes get pulled over its nose without it! What a great idea to add the gullet strap and solve the issue! (I'll be putting a picture of this hanger online this weekend if she gets it back to me after trying it on).
A sidepull is a bitless bridle that works better than a halter because it's designed specifically for riding. The noseband sits lower and there's less twisting.
A sidepull noseband is just the noseband attachment that can be put on a regular headstall. I make both side pull bridles (all one piece) as well as nosebands that can be purchased separately and attached to your current tack or paired with one of my headstalls. You'd only need to get a sidpull bridle or
the noseband attachment, not both since the sidepull bridle has the noseband built in.
A chin strap is the non-metal version of what an English rider would call a curb chain. It's just a difference in terminology ;) You don't really need it with most snaffle bits, but you have to have it with a noseband (since it holds the noseband in place) and I think there are some bits that require a curb chain or chin strap.
The difference between the one-ear headstall and split-ear headstall is really just preference. The split-ear has a throat latch and the one-ear doesn't, but I can make it with one if you'd like. The benefit of a throat latch is that the horse can't shake/rub the bridle off as easily, but you can usually do ok without it if your horse isn't shaking or rubbing a lot.
I would recommend sticking with something similar to what is currently working with your horse if he's young and still needs to have a lot of reinforcement and training. However, I break horses in side pulls with a few noseband knots for a little extra pressure - Indian reiners work well for this since they apply pressure to push the horse's face away from pressure on the opposite side. I don't recommend a side pull if you are worried about your horse running out. How does your horse respond to a the halter (and are you using a flat one or a rope one with knots)? If he's respectful with the halter, you shouldn't have a problem with a side pull, especially since you'll get more leverage in a side pull as it sits lower on their nose. If not, you'll want to work on respect some more before you move to a side pull.