Unless you are fairly experienced, I stay away from the draw reins. If you want to use something, a running martingale is much bettr. It stays out of the horse's way when his head is where it should be, and only engages when he puts his head up. And then there's an immediate release when his head goes down. With draw reins, you really should be able to use the regular reins and the draw reins independently.
My suggestion would be to use the running martingale and practice lots of trot-canter, canter-trot transitions. Usually throwing the head up at the transition shows a lack of impulsion. Do a posting trot, down to a sitting trot with impulsion, and then to a canter. Make sure you aren't getting ahead of the horse when asking to canter, but staying a bit behind the motion. JMO.