I just recently purchased a Belgian mare that is trained to ride and drive. When I asked her owner what type of bit he used on her, he said snaffle. He indicated to me that she is not trained to neck rein, only direct rein because she drives. I have purchased a draft bridle and measured her for a snaffle bit, but during my research I found a side pull bridle. What exactly is this and is this what I should get for her instead of a regular Western bridle?