I'm working on loose leash running. I would say our dog does well about 80% of the time. He does well ignoring other dogs on the trails but will consistently lunge if he sees a squirrel.

The second issue is that his behavior deteriorates a bit when my girlfriend is walking him.

We are currently using a half-choke collar. I feel like the collar corrections are usually effective except when small woodland creatures are involved then it takes several fairly stiff corrections to get him back into a heel position.

Thoughts on the best way to further refine our running technique?