Nice to hear he came back.

I know you probably don't like choke collars, but why not consider one as a back-up. You keep the snap collar on him, but place a choke collar on too, snap onto both collars that way if one does break away, at least you have one that won't.

We use this combination with some of the mellower dogs in rescue. The snap collars is the primary and the choke collar just hangs loose unless the other one breaks.