Using a rope or bar handle attached to a cable that's set above your head, do a set with an upright torso while standing about 4-5 feet back from the cable column (8-15 reps).
Then do a set with your torso parallel to the floor.
The point of maximal mechanical tension is when your arms form a 90-degree angle to the cable. So, upright torso pulldowns focus more on training you in the shortened to mid-range aspects of shoulder extension. Performing them with your torso parallel to the floor focuses more on the lengthened to mid-range.
How does an advanced lifter build bigger arms? Is it even possible? It is. If you're an experienced lifter who hasn't seen arm growth in ages, here's what to do.