Training An Impulsive Border Collie

I'm still working with Pogi to get him to mind when he's off leash. Halo, my Aussie, spends most of our walk wandering free, but Pogi is now only off leash in a specific place. Before, I was giving Pogi too much freedom, and setting him up to fail, and then getting angry with him.

Now he gets to practice following the rules in a spot where he's almost always successful, and he gets no anger and lots of praise. There's a distance where's he's still under control, and I have to watch him, and not let him get too far out before I draw him back.

When I first got Pogi, I thought he could just watch Halo, and follow his lead, but it just doesn't work like that. They are very different dogs.

Also, two stray dogs so far today. A big black/white pit bull, and just now, a little chihuahua.
The pit bull advanced, but stopped short when I warned him off. The chihuahua had a collar, and just cruised by..maybe he knows his way home. Neither dog listed on Craigslist lost/found.