This exercise is about developing control and stability, so don't feel like you have to lift super heavy weights. (all-about-arm-exercises.com)
It's basically the aspect of challenging your body with super heavy weights and low rep ranges, with 2 - 3 minutes rest between sets that helps to maximize T production. (truthaboutabs.com)
If you want to build big trap muscles, use super heavy weights, and if you just want to support your posture and shoulder joint use lighter weights. (all-about-arm-exercises.com)