How do you pick your pups

When pups are 6 or 7 weeks old, I just dont think it matters which one you pick. If it is a well bred litter, there is no way to pick ability in a pup so just grab one that suits you & go with it.
I have kept runts before & they turned out to be just as good as the others. Now I tend to pick one that is more in size with the average of the litter.
You can definently change the size of your dogs. If you always pick the biggest male or the biggest female you will see a increase in size of your dogs in just a few breedings. Same with runts.
I really believe that it is not which pup you pick as how much exposure & hunting a pup gets as whether he makes it or not. My dogs do not do good staying in a kennel until they are a year old & then taken out & I dont believe anybody else's dogs do either. JMO