[Rather than try to quote everyone and reply inline, I am just going to add my new current understandings or clarifications -- or questions. And again, thanks to all who are helping, I really appreciate your time and attention.]

As to multiple jabs, I absolutely agree and had thought to put that in the first post, but decided my long post to stand some simplification. So I think this question was about the power jab, since my coach is riding me to develop that -- with speed and no hesitation or delay when doubling. My biggest current problem with THIS type of jab is keeping the power without introducing a delay, especially as my arm fatigues after multiple rounds.

I think if you have a clean fast power jab, you can always tone it down for distance measuring and distraction, but doing the opposite isn't likely to be as trivial.

In my opinion, my jab has little or no telegraph characteristics, and goes out (and back) very relaxed -- even though I am new at boxing, I have a couple of serious years in Systema where (practically) every punch is relaxed and thrown ballistically, usually with a definite strategy of concealing the actual punch. Sure, I can improve here, but these are current best attributes, along with hitting hard -- that is, at my current level. I will need to improve these again as my current weaknesses catch up, an continuous, iterative process the Japenese (businesses) call Kaizen.

My tendency to hesitate between jabs when throwing hard isn't about telegraphing, but merely a neuro-muscular delay to 'find the power' again. Likely this is just going to take driving myself to and through exhaustion for few weeks/months, until either the muscles or the nerves (both really) respond faster even when fatigued.

I also agree with the "getting the elbow" back -- I find this makes a much more reliable mental trigger for retrieving the hand/glove back to guard. If I concentrate on snapping the elbow down and back to the body the hand MUST end up where it belongs, but merely pulling the hand allows the hand to end up almost anywhere...
I finally got in a little 'shadow sparring' -- no real hitting -- with a bunch of more experienced young guys ages 20-35 -- and got to see where all this practice is taking me, at least to a small degree. They all noticed my continued aggressiveness (moving forward, jabbing my way in) and my defenses were much better than I expected, both catching their shots and (wonder of wonders) moving my head. (My only real disability is some chronic arthritis and extremely stiff joints including the neck and spine.)

But, I started slipping and ducking punches at their encouragement and it was surprising (to me) how many I could just avoid and immediately counter punch successfully.

Only problem with this is that I cannot really tell what works since they aren't really hitting me even though I tried to encourage them to put more into showing me my weaknesses -- really, I don't mind being hit and it's the only way I can really know if what I am doing is working even though I feel no real need to add real contact to hitting them.

I watch a lot of boxing on TV -- my wife likes it too fortunately -- and of all the fighters I see, I think I am most like Glen Johnson the light heavyweight. Although I am seriously working on cutting angles (from Systema and AMOK!) and not just going straight in every time (my natural tendency).

Johnson is about my size -- I outweigh him by about the amount of fat I need to lose, ~20 lbs -- and build except that my arms are a bit longer for my height.

I do not however want to be limited to just one such style of fighting however.

Thanks again for the continued help.
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HerbM