I know most here rescue , but thought you might be interested in how some breeders including myself do part of the evals on a litter
Puppy puzzle is a great tool that teaches you how to eval a litter more accurately
A pup at 8 weeks as long as they are not born premies or have some other major health issue will pretty much give you a good idea of what the dogs adult structure will be; as seen in the below picts I took of Samurai who was a puppy out of my litter. Here is the day I did the eval and him as an adult. LOL almost the same pose too, what a brat
week 8 Oh mom, just give me the dang cookie this show stuff is making me hungry
Samurai the weekend he Championed:
the link so you can read more on it, if you are interested
http://www.dogfolk.com/