You're explaining fine Brian. On a walk, what matters most to me is that its clear to him when he is expected not to pull and when he is released from paying attention to me and allowed to be dog and sniff, look, jump on, whatever. Its ok with me if they pull a little when they're released. Just exactly like you said, not towing you around.

I'd be careful not to blur your formal ob with walks and hanging out. I think the most useful thing I do to teach my dog not to pull too hard is to just hang out in one place and not let him pull. On a walk I just say easy and give him a little pop. Using the leash pressure all the time, I'd worry its going to condition him to always pull and it will be less useful in your formal ob.

The micro prong is fine. You can use it on ANY dog. If it works, it works. If a fur saver, a nylon choker, or a flat buckle collar works, it works. Training is about making things clear to your dog, no matter what your using.

Nagging is something thats ineffective or distracting to the dogs focus. You can nag by saying good dog too many times and you can nag him by constantly tightening the leash trying to stear him around. It generally leads to them ignoring you, but you can get a little more of a reaction out of them with it sometimes too. Nothing good.

I'm kinda thinking you may be doing a little bit of that. When you say you pressure him down, I'm not sure your able to make clear to him what you wanted. I know he's young, but I want him to know he has to down. Downward pressure everytime is you doing it for him. If he isn't comfortable downing around the other dogs yet, keep a little distance so that HE can do what you ask. Does that make sense?