Lin,
Bo is absolutely beautiful! I can imagine how strong he is! I think I may have something that may help you and will not cost you a bundle. It is as simple as going to youtube and put "kikopup" in the search area (no quotation marks). You will be in for a treat. Short easy lessons by one of America's rising trainers. Videos are only a couple minutes long but it is somewhat important to learn to use a clicker, not that it can't be done without one. Dog treats that Bo values greatly are important as well. I use kibble around the house and very small pieces of leftover meat when out working the dogs outside or in a pet store. I would choose the lessons of "Watch" (some say "Look") "Come" and "Leave It" first since that is something you need right away.
For walking I use an "Easy Walk Harness" with a fastener in front which directs the dog back to me. When the dog turns towards you, click, treat. I would follow Kikopup's ideal method for not pulling. If she says get another harness, I would follow her suggestions because I don't know the newest equipment these days. After watching her videos, you will understand more. If you have questions, you are free to ask me. I may need to know which video you viewed, there are so many! You may not have to find training at all.
Remember Bo is a teenager about now which is part of the problem....!
This is Frankie, my 10 year old, blue eyed Mini Aussie. He picks stuff up for me around the house.
This is Jack-Jack, an 11 year old, Italian Greyhound who was a stud at a puppy mill for 3 years. He was afraid of anyone and everyone at first.