We spend a lot of time trying to teach athletes how to shut lats off when they shouldn't be on. However, I know we aren't going to talk you out of trying to develop that V-shaped torso with lat work, so what are some guidelines?
First, you aren't allowed to do pull-ups or pulldowns until you pass the back-to-wall shoulder flexion test. No exceptions allowed.
With mechanical drop sets, instead of reducing the load, you switch to a new but similar exercise by changing the grip, angle, etc. The result is a whole lot of burning and a whole lot of growth.