Do not go fully positive. Fully positive is for trainers and puppies. I can't go fully positive with my 5 month old, never mind a fully grown adult!I am thinking right now about using some savings towards another trainer (last one on the list), since the one previous to this one was also a bad story I do not longer have that much faith in trainers.
Right now, we have been taking him to 'not so crowded' places, to be honest I do not feel as confident as before. Hence, we are moving towards people slowly. I do not like using the prong collar that much anymore, thus, I am looking for something else, probably a slip lead or a fur saver. Not sure yet, I am still reading and such. He has been acting braver, though, and that is a change, he has been climbing and jumping on things. Yet we had an incident he lunged/snapped at his Groomer the other day (though he had just spent the night at the Vet clinic cause he got poisoned with a a plant and was still on meds, I put him on a down position after and he remained calm around the person), but we have been walking around people this past week with no issues. Dogs on leashes and stray ones (many in Mexico) have been a case by case situation, distance has been our friend.
Going to really try to get my cousin's dog after New Year's, our dog does not hurt other dogs, he used to try to herd them, and get his space. But I am pretty sure I can use a muzzle if that helps my cousin or anyone feel more confident.
Regarding books or online training options, -that is something else I am considering-, but, I am not sure, for example there is Leerburg's website and their many on demand videos, they have one for reactivity, they have one for aggressive behavior and another for structure, and also there are other trainers with videos, I am really confused right now, about which one to pick or which one to start with. Most books I found are strictly positive, and with a 100lb dog, it is really hard to go fully positive.
Real thanks for your last paragraph by the way, outside of my dog, this has been quite a year, and considering I ended up this year with Odham the same way we finished last (with no trainer and still having issues), I feel like my decisions are a constant failure. But then again, we are not giving up with this guy, on the opposite, just looking at small improvements and that is good (he remained calm on his crate in the living room the other day while the IT guys changed the wires and some devices just next to him).
All the trainers recommended are all good. I recommend Leerburg personally, but others here like Jax08, LuvShepherds, Thecowboysgirl, and many others have hosts of others that might help even more. Just choose one. You'll probably want one to address the reactivity first, then you can move on to get structure and develop more confidence. But I'm not really the one to know.
I'm glad you like the pep talk. I learned it from my horse riding instructor, who says to just get back on the horse if you've fallen off and swallow your fears. it is a great principle, I believe, and I'm glad you could get some help from it too.
Prongs are the best! Unless your dog's fur needs saving, just use the prong collar. It is the most humane, gentle way to do it and it has worked so well on so many dogs.
I'm glad to be of some help, and to hear he's doing better. Leerburg is great! You should absolutely try them if you can. Good luck.