And I wouldn't support a breeder who let me run among a litter and then just pick the one I felt was right! The breeder will have known and been with the puppies for weeks and I will, at best, have a few hours on one day.
The reason I pay the big bucks is exactly for the knowledge and experience of my breeder with their pups! They have had past litters, testing the pups and then seen them grow up to see how true the testing worked out!
Heck, I'd just pick the one that crawled into my lap, or had the cute bent ear, or ..... and that's not really probably the best thing