I have a friend who has the underground type. The V is quite strong willed and will run through it if there is something interesting enough on the other side. Typical V, the most interesting things are visitors arriving!
I practice recall alot with my V. Put something out she really wants and then tell her to get it. When she is about halfway there call her back. There is a bit more to it than that but it is useful when the dog bolts off. It usually takes a stern, loud NO in those circumstances and you have to get used to people looking at you. But it works and is beter than a flattened V. She has learn't this quite well now. Was at the beach on Saturday and she was wandering off to see some other people walking the beach. A quite Nooo from 15m and she would look back at me and stop and watch them walk by.
Whn you get control it is quite rewarding but the dog must get reweard and have fun as well. The V came home from the beach wet, dirty and tired. We call this the Dirty, Wet Vizsla. These are the best sleepers!