<human>: Alright so, this Sunday, I have the opportunity to go check out my potential second dog (Border Collie, working lines). I've never encountered puppies younger than 8 weeks, and I am kind of hoping to "gel" with one above the others to make my final decision easier. But! I have read that the ideal time to test these things is at 49 days. Any younger and it could change my judgement.

Have any of you had an experience with picking out your pup at 4 weeks, when visiting the litter? Was their behavior and likes/dislikes consistent with what you ended up getting at 8 weeks? I'm not paying attention to looks at all - the only thing I want is a pup who enjoys toys, play, and has a lot of potential drive to tap in to. Ace, my current dog, is aloof and independent, and I have had to overcome a lot of obstacles to get to his current state of biddability!

Can you give me a shortened version of the text?
<bot>: Going to meet possible pup who will be 4 weeks old, this weekend. I will NOT be taking one back home with me - I just want to test the waters for temperament/drive. Can this work?