First, I can appreciate the frustration as I have been down the path of dealing with a reactive dog.....it was a new experience for me and I made myself vulnerable to all the "fixes" and the "guarantees" many trainers offered.
Because of my basic nature....I pursued the least aversive methods first....these methods may work on a very mild reactive dog but didn't seem to be the ticket for me and my dog...so I proceeded to the next method and "guarantees"....basically about the same story....some improvement but still not acceptable as far as I was concerned. I even compromised my "basic nature" and did the e-collar method ....once again...some improvement but still not what I was willing to accept as a final solution. Actually, the biggest improvements in her reactivity came through all the obedience work we did...the more obedient she was....the easier it was to keep her check with her reactivity....made sense to me. But, still not there yet,
My good fortune brought me across a gentleman ...a retired LE K9 handler who still trains LE dogs....I told him my story and he took me under his wing....he had me attend some K9 training sessions and worked with me during their lunch breaks. This is where I was introduced to the dominant dog collar and the proper way to use it for dog reactivity. I have found the answer as the two trainers who deal with me seriously know the breed and how to deal with this issue....plus it's great being around a bunch of high drive dogs which most all of them had similar reactivity issues as mine earlier on in their training...if not a ton more. Being in that environment was living proof...the "guarantee" was right there in front of my eyes.
Now to bore you more...some observations and realizations. My use of the prong to correct this problem most likely was just ramping the dog up unless I caught the dog well before she was about to light up. The correction from a prong if she was full on...would probably need to be more severe than I was providing...and worse yet..when I would get closer to that level...I was anything but calm and composed....my emotions were running high as well...it was a lose/lose situation. The use of the dominant dog collar and application is entirely different......no yanking...none...just steady upward pressure AND in doing this....it had an effect on me...I was keeping my cool....
I had heard in here at times thoughts such as ..." a few potent well-timed corrections is infinitely better than many ineffective lesser corrections"....I understand that now...I obviously didn't then. Yeah, I might annoy my dog using lesser prong pops at times but it isn't to deal with issues like reactivity...more just to keep the dog in line with obedience skills if she is having an off day.
I also remember Slamdunc stating that most handlers think their dogs are more severe in their reactivity than they truly are.....this I have found to be true in my situation...I base it on the fact that the amount of full corrections I have had to use with the DDC is incredibly less than any other method previous......I'm talking like a total of 6-10 full uses of the DDC to date...and the results are better than all the rest of the methods combined...yeah, much of it could have been handler error on my behalf but I was under the tutelage of "professional" trainers...that's the excuse I'm going with
Just a suggestion, if you could check around with your local LE and find out who or where they get their K9 training done...it might open some doors and help you out tremendously. I know they aren't necessarily in the business of training JQP's dogs....but if you are lucky enough to find something like I did....I'd give it a try. Like I said above....these folks truly know the breed and know their training and they don't patronize you or sugarcoat your failings in the process...I like this fact.....plus they are incredibly nice people...especially to ones with GSDs and Mals.