Actually, the first thing you'll learn is that they do know exactly where their horns are and they can get them maneuver them in the most amazing manner. Our longhorns can neatly swing their horns to the most unbeleiveable spaces, you just have to allow them time to think about it rather than forcing them through. The stanchion idea may very well work, if you can gently work them that direction, I have a friend that AI's with no chute of facility, she simply pinches them in a corner with a gate or portable panel. You can usually rent panels and build a small pen and alley. IF they're really wild, I'd recomend spending a bit of time with them before you AI. They tend to act a bit like deer so you want to start by letting them become familiar with your scent, just stand out there with them until they relax quit milling or heading off. They tend to like it when you bring them treats, a bit of grain or something like that. They do calm down pretty quick. We had an old range cow that was pretty well wild and after about 6 months, her and her 60" of horn were following my daughter like a puppy and eating out of her pockets.