Thank goodness you were able to get him to come back to you, especially avoiding 309!

Have you tried something like this yet?
http://www.sassypup.net/Dog-Harness-...K-p-16671.html
Do you leave his harness on when you are not home? Chip chewed through a regular nylon one, I tried the gentle harness which works great for Harley but not too well for Chip. Now I have a Puppia Harness, I only put it on him when we are about to go out for a walk. I like the Puppia because of its soft construction, the nylon on the gentle harness irritated the skin under his armpits.