Montague
Yeah, lowering the bar behind the head puts the elbows in a closer range of a straight up & down position, giving more of a direct focus on the triceps themselves. And doing away with any pressing motion, and becoming more of an extension movement it was intended to be. As I have mentioned many times before, the elbows will usually lead the way, and in return have a greater influence on the path and result of a exercise.
People don't need to fear giving the elbows joints/ligaments and tendons punishment, if knowing how to strengthen that complex through logical training. There are certain training programs that can almost insure durable and strong joints. Thing being, most guy's lift too heavy, much too often and going to failure on just about every set, every workout. Self defeating, if nothing else.
Wise decision on your part about the slow and controlled negatives. Negative training can become very important in anyone's training plans. And yes, JM pressing can be very rewarding. Gironda did a version for lighter BB'ing exercising and of course the pump. Actually I don't think there are any true new exercises in lifting. just other versions and training protocols.
Keep up the good works and stay cool,
Good luck.