If you cannot see both parents run, the most reliable way to know they are top notch dogs is through field trials. The more recently in the pedigree, the better. The work that goes into a dog that can compete and win at that level is extraordinary.
You can get excellent dogs that have zero FC titles or even placements in their entire pedigree, but you have a better chance with dogs proven by unbiased judges.
Any Tom, Dick or Joe will tell you their dogs hunt great. They may be right. But if someone shows you an FC titles in one or both parents, you have a special puppy. Even just a couple of placements shows that the dog can run and is fully broke. Proven parents do not guarantee the pups will all be great, but it increases the odds dramatically.
I am a bird dog trainer and breeder. I see and work with many breeds of dogs from a variety of parents and pedigrees. I have had a dog taken from a shelter at 5 years old turn out top notch, but I consistently get the best dogs from lines that were proven.
Another thing to consider is getting them from a pro trainer. The reason I say this is twofold. First, a trainer knows what is decent, good, bad or extraordinary because he has seen dozens of each. Secondly, a pro trainer will likely only want to breed and sell the best he can because if you hire him to train the dog, he cannot call you back a week after dropping the dog off and say the dog is shit and is scared of birds.
I would, however suggest against getting a dog from two All Age Field Champs. If you breed two all age running dogs, about one or two in the litter may run that big, which would be useless to a foot hunter. There are databases online that show any AKC field trial placements online of any dog. They will tell stake and number of dogs running. Puppy stakes (6-12 months) soley judge running. Derby stakes (12-24 months) judge running and they have to point a bird and hold it until handler is in shotgun range to be eligible to place. Gun dog and all age are adult stakes. All age dogs will run 1000 yard patterns. Gun dogs run closer in. The dog must back (honor) perfectly and be fully broke and have at least one find to place. All points and backs must be completely perfect and through the shot until manually released by handler. If the dog has five finds and a perfect back, then finds a sixth bird with a minute left and takes one step after establishing a point, he is done and cannot place.