Serious set of 'nads on that Viszla there...
I've got a working cocker spaniel myself (not the more common and more urbanised show variation). It's also a breed with a tremendously high energy level. I find that if he's taken out for two long walks a day, he's fine. one walk of half an hour and another of an hour plus. This includes a decent session of ball-throwing, as this is the canine equivalent of interval training and wears them out good and proper.
I also take him out whenever I go for a ride. He'll come back dirty as hell, but will love you all the more for it. If it's a long enough ride he will be pretty worn out even into the following day, and you can skip the fetch session. I haven't trained my guy overly much, but have developed a decent recall. Use a whistle, because if there's a forest near you and he takes off after deer or rabbits, he'll be out of voice range in no time.
Overall, it's awesome having an energetic, intelligent and friendly dog. Can't help it, but I do sometimes feel sorry for those with ankle-biter yorkies or scotties, because they miss out on so much of what owning a dog can be.