Don't worry about the grip . . . . at first.
Consider how the arms "track" down from overhead to wherever they come close to your torso, they can both travel thru a semi-circle that is all in front of you, or they can each travel thru 2 separate semi-circles out to the sides, and the effect on your back will be different. Notice that using a 2 hands over the bar grip, even when the hands are moved in close together, tends to still flare the arms out, you pretty much need an underhands or parallel grip to get the arms tracking in front of the torso, and those narrow "triangle" grips still flare you out a bit. Even an underhand grip on a straight bar with the hands close together flares a little unless you move the hands out, just watch where the arms "track" when you choose pulldowns and rows.
Notice too (three?) that if you alternate back workouts, you might want to pair rows and pulldowns with that where-do-the-arms-track idea in mind. Like, pair an arms-in-front pulldown with an arms-outwards row in one workout, alternated with a workout where the arms in the pulldowns and rows do the opposite.