There is too much metal there, plus you could not open the gate without getting zapped yourself. I have hade the electricity jump from the fence to gates, barn and round pen at times. You kind of hate to touch anything metal.
Never tried them for horse panels, but I was thinking they make something for those panels. That way the metal it not close to touching the hot wire. Also, at the gate, there is a plastic hook with metal on the end that touches a metal clamp so the electricity runs through it. When you want to go through the gate, you just unhook the plastic hook from the clamp and all electricity is cut. We've used those and they are great!
Those would work. Larry has tried to adapt that style of insulator, but they had clip-ons, not very successfully. I would think the style shown on your link would do it, though.
These are a good idea, but there are too many openings that a Mini can stick their head through, you would have to run several lines of that and as I mentioned before, I have had the hot wire electricity jump from the wire to the pannels, and even to my barn. I try to keep all hot wires away from the metal round pens.