What is your objective of deadlifting? Hypertrophy (size), strengh (max weight you can lift), or power (increasing the speed at which you can lift a given weight)?
Such will determine your sets, reps, %rm, and rest periods. Rest periods actually will have the greatest impact on the hormonal response. Shorter rest will result in a greater GH release.
That said, I see a few problems with nearly every deadlifter. First and foremost, it is a DEAD lift. This means you are starting from a stand still. This is not tapping the weight off the floor and jerking it up again with your back. Its putting the weight down, regripping, resetting your hips, and lifting in good form. When I train with bumper plates on a platform, I don't even lower the weight, I drop it to the floor.
Second, is pulling form. The deadlift is a posterior kinetic chain dominated exercise. This mean the glutes and hamstrings are doing the majority of moving, with the lumber back muscles finishing the lockout of the movement. Too many people have over active hip flexors, tight hamstrings, and end up moving the weight predominantly with the lower back (ie. hips elevate before shoulders). In a correct deadlift, the shoulders and hips will elevate at about the same time.
Br