If i've got a choice on a litter , i go for the one that shows the most drive ,get them out on their own one at a time, somewhere neutral, garden or maybe a room in the house, and throw something soft, the pup who chases and retrieves back to the best of his ability is a likely candidate ,,you should be able to narrow it down to a couple of pups after that , after that its which ever one takes your fancy,, good luck with it,,
spot on