I do both, hands facing the bar (pull up), hands facing back toward me (chin up). They are two different exercises. If you can not do one good form pull up, I would either use a weight assited pull up machine, or if you do not have access to one use a chair to help . I would think pull downs would help also, but I found that using the chair to help improved my pull ups faster. For me, the wider I spread my hands the harder it is. Right now I think I am a couple of inches outside my shoulders and I am working on getting them wider.