The musculature in Helm's edit is more detailed/accurate, but the arms are too small, mostly because the shoulder muscles and overall mass are reduced too much. The best way to gauge correct propotions is to hold your arms down, and take note of where the major body parts lay. I'm a tall guy, so when my arms are at rest, the elbows end about 2" above my hips, and with fingers extended, my hands end about 2" above the top of my kneecaps. In the original, the arms are ever so slightly elongated, due in part I believe, to the shoulders, which look a bit saggy/too far down. Work off the general muscle study of Helm's edit, but stay closer to the volume of the original, and you should get what you're looking for.