I have really enjoyed your site and the quality section in the knowledge area has been an interesting foil to evaluate my technique. It's with some trepidation that I wanted to ask what you define as an active shoulder position at the bottom of a pull-up? Thanks for your time, as well as what you have shared of Gym Jones with us outsiders.
The best description I can come up with is not hanging solely on connective tissue. If you dead hang from a set of rings, roll the shoulders down and "back" so the head of the humerus is in the proper position, your elbows will have rotated forward and there'll be slight (10-degree +/-) bend in the elbow. This is a good position to begin from, especially when connective tissue isn't well-developed yet or fatigue might cause you to drop onto a hyper-extended shoulder. One goal will be to develop connective tissue well enough to prevent injury so static dead hangs and dead hang pull-ups should factor in to the training but it's not all dead hang all of the time because a) that's not how you use the joint in actual application, and b) varied positions should be trained. Regarding pull-ups everyone has an opinion on what is good technique and what is not. Many consider what we do "cheating" ... so what. Good technique puts your head all the way above the bar, and gets you into and out of the bottom position over and over without getting hurt, but also without ruthlessly short-stroking the movement, and good technique may also be defined by the fact that it makes you stronger at pulling. If the results are good, and what you want, then technique need not be the foremost consideration.