Puppy pulling on walks, slips his collar... choker, martingales, harness?

Sorry, I couldn't read your whole explanation (don't have the time), but if your dog is constantly pulling you, there is a harness that is called "No-pull harness". It fits very similar to a regular harness but no matter how much your dog pulls he will not pull on you. I thought it was kind of weird but I needed something for my pug and it really works. Part of it goes over his shoulder.