The chin-up and its variants are the king of lat builders, If one wants to do them to rep the benefits, then finding the right hand spacing is critical and different for most and a compromise is needed.
visualizing this will help you understand why hands spacing is critical;
sitting in a chair holding a pencil in each hand bring your arms down by your side, notice the angle of the pencils, now extend you arms up above the head, and notice the angle change.
you'll notice that most people will feel a lot more comfortable with palms facing...as opposed to fully suppinated as you experience shoulder wrecking impingement over time.
unforunatly palms facing more often than not lead to painful elbows.
some pull down machines offer rotating handles with this in mind, whereby you start suppinated at contraction, and rotating the hands as you move in to the stretched position minimizes shoulde impingement, if you like chinning and have issues, these machines are a must.
i think the best modern machine (without rotating handles) produced by far is the Hammer strength high pull, the movement is the only one that effectively contracts the lats, where most of the magic happens in all exercises.