A Bit of a Dilemma

Walker is strong.  That became clear to us 3 minutes after I first got him.  Most of the lesson horses at our barn ride in a simple jointed D-ring snaffle bit, so naturally that is what we put my new horse in.  Like I said, it took all of 3 minutes for us to go from that to a shank bit with a high port.  Here's the difference (for you visual folks like me):

We went from this:

To something like this:

I'm sure even those of you who know nothing about horses and bits can see that Walker needed a much harsher one for me to even remotely be able to control him.  That being said, I have been through quite a few bits with Walker since then, and we no longer use such a harsh bit on him.  I still use a type of shank bit in my Western bridle and an Uxeter Kimberwick with a low port in my English bridle.  I'm sure that's all jibberish to you, but bits are kind of a trial and error thing.  It's also very important to understand what they do and how they work.

So I've been doing a lot of reading, mostly because, from very early on, Walker liked to drop his head low (as in, lower than he even does when he's behaving as a Western Pleasure horse) and get behind the bit.  Usually he would then run away with me at his own speed or else throw me a good buck or two.  I should premise this conversation by saying that Walker has never bucked my instructor (his trainer), who was the one to pick the current shank bit I use now, and it is clear that Walker was handled in an even harsher bit (by an experienced rider) at the last barn he was at without any problems.  With that knowledge in hand, I'm starting to think that a shank bit is what Walker needs, but is not necessarily what I need.  I'm starting to suspect that his new problems (i.e. bucking) are actually caused by me (my position, and most importantly, how I use the bit in his mouth).

I think I force him into a position where he needs to get behind the bit, and to punish me for punishing him, he bucks.  I've read article after article that says that a shank bit exerts a lot of pressure on a horse's mouth and shouldn't be used by an amateur.  I think we can all safely agree that I am an amateur.  That being said, I feel like I could use a shank bit on another horse (and have actually done so), but with Walker (who is so strong and has an unavoidable track record of taking off on me), I simply hold it too tightly and exert too much pressure on his mouth.  I have been unable to find the perfect balance.

So I'm considering buying myself a new bit (other than the three ones I already own...), and seeing if that will improve his responsiveness.  If my problem then becomes that he takes off on me or can't be turned either which way (like I said, he's strong - it has happened), I will know that the shank caused my current problems and that I either have to get a handle on that or start lifting weights.  Hopefully, we can find a bit that works for both of us, and ironically enough, I think I'm going to end up going back to the bit that started it all.  In other words, this is a disaster in the making...