Bits?? help?? pleaseeee:)?

Hey guys! Alright so I need to find a bit for my barrel horse and was hoping you guys could help. You don't have to give me an exact bit as you have never seen my horse but just some info on how to pick a bit (what the different types do, size shanks, etc.) Last year I ran him in a twisted wire Jr. Cow-horse and we had a lot of problems in that. I feel as though a lot of the problem was control however. I was a green rider and let him take off with me and he would often run up the fence. Since then we have been training and doing different exercises. I have ridden him in a type of pleasure bit to slow him down while we were training. However, we are now to a point where he will walk in the gate, listen to my cues, and go around the barrels. As a result, I am ready to move to a different bit that will still give me good control, feel, bend, rate etc. But also allow him to run with out me having to push as hard as i would have to in a pleasure bit. I'm really not sure what to get him though and have been experimenting. The bigger problem is my biggest show is coming up FAST (like a few weeks) against tough competition. I really want to qualify at this show for the next show thus, I don't want to still be trying to figure out a bit the week before. I know this is rather long, but i TRULY do appreciate any help! Just some info on what different bits do. Thank you SO, SO much!!