I like his butt and his back is a good length. The way I would start a barrel horse is walk him in the clover leaf pattern around the barrels over and over until he knows it. Then trot. When you trot him around the barrels you can canter on your way home. What I did with my horse is I used two barrels and did figure 8's around them and obviously had him change leads lol. After that I added the third barrel and we flew! Barrel racing is a lot of fun. When you go around turns you use your inside reign to turn him around the barrel. As for bits everyone recommends different bits. Research the bits people recommend and see which would best fit your horse. A great place to look for these bits are at a used tack store. My barrel horse uses a hackamore so I shouldn't be recommending bits for this discipline lol! I hope I helped!