I am beginning to lay the foundations to defensive training with my 10.5mo GSD. He has exibited some defense to this point (out for a walk in the yard at night and some local kids walking home cutting thru yards on their way home). Med-High prey drive. Stable around fireworks, gunfire, cars etc.

Per Ed's vid I want to start to get him used to/comfortable with being tied out by himself in public places, as Ed recommends as a first step.

He is great on leash in public (with occasional puppy moments). Just today I stood around outside a supermarket with him on the leash. No issues. People and cars going by...No proble. Talking to people.... No problem. People coming up to talk and look at the dog...No problem. Old lady coming up and putting her hand down to let the dog sniff her hand so that she can pet him (I know, I know.. but I can't turn down a nice old lady)....watched her carefully, then gave her a quick sniff on the hand one or two tail swishes and that was it... evenually layed back down. Not skittish that I could tell.

Tie him up to a post and stand around within 6ft of him... no problem.

Turn my back and take two to three steps walking away from him and he starts barking at my back and raising holy hell....come back and he stops.

What's the best way to progress past this point?

Considering that I was doing this almost directly under a "NO DOGS" sign and about 15ft from the entrance to the store, I was understandably reluctant to let him bark and go crazy.

I'm leaning towards just keeping on keeping on...working on walking away from him until he gets more comfortable, but I'd like to know if there are any finer points that I am missing!

Thanks!

"trust" is the key for any exercise. Your dog has to trust that ,when you leave him behind he know you will comeback. Start with small steps first. You can practice on a field , you don't have to be in front of a store to train the foundation to teach him to be left on his own and wait quietly for you to return.
When I teach any exercise , I teach in small steps. Put your dog on a back tie to a tree at the park. Take a few step away ,for a few seconds, return to him tell him good boy for waiting & staying there quietly. Leave him again, go an extra step away, return to him every time you leave, let him know he's being a good dog, keep practicing that and go further and further with quick returns to him , then as your training gets along, stay away longer and longer. Let him know that no matter what you return to him. Dogs are pack driven animals, their instinct is to follow, back tying him and leaving him ,will make any dog vocalize that separation! The first time you leave a pup in a crate or a room he will always vocalize you being away, but as time goes by and he learns that you always come back, they get used to it and they QUIETLY wait for your return. It is the same concept! Start with small steps! I can back tie or leave off leash my dog anywhere and he'll wait for me, I have him on a down the whole time I teach my OB class and he waits patiently. He knows I would never leave him behind and not return.He has full trust in me. Makes sense? Good luck..

Gotcha.

Will continue to take him out in public parking lots etc. on leash, but won't tie him up and work on walking away until we have some success in a more quiet environment.

Too easy.