If you want 4-5 pounds as adult, try to get a puppy who is 2-2.5 pounds. It is
not a quarantee

, but simple math is
8 weeks * 3
12 weeks *2
=
adult weight
I wouldn't take a pup at 8 weeks. I bought my pup at 16 weeks. She was 3. Now she is 5.5. I care her around EVERYWHERE, even restaurants. NO problems (except restaurants and food stores

)