Updated: Oct 5, 2019
Searching for that "Mini Pomsky" is very unrealistic. Yes some Pomskies can be very small but searching for the Mystic Mini Pomsky can also leave you wide open to scams and unethical breeders. Pomskies come in all sizes and a litter of 4 to 8 can throw several sizes. If the breeder knows her dogs and weighs from birth they should be able to estimate adult weight within a couple lbs.
Tiny is 10 - 15lbs full grown so as a puppy this will generally be a 4 - 8 oz baby Pomsky(birth weight)
Small is 16 - 25lbs full grown (average Pomsky) will generally be 9-13oz baby Pomsky (birth weight)
Medium is 26-35lb full grown Pomsky this will generally be an F1 Pomsky (Siberian to Pomeranian and weigh 14-17ozs at birth weight
Large is anything over 36lbs and this puppy will be between 1lb and 20oz at birth.
Unethical breeding would consist of a "Reverse breeding" also done with Huskimos .. the mother is the Pomeranian, Eskimo or Pomsky and dad is the Siberian or larger Pomsky. This is done to create smaller puppies but the part that is deceitful is a 6oz puppy at birth can turn into a 40lb dog as an adult because the puppy adapted to the mom's smaller size at birth and then balloons during the growth spurts.
A real Pomsky - Siberian/Pomeranian- will generally have two growth spurts at 4-5 months and then again at 7-8 months reaching almost full adult weight by 10months. Like humans they will gain 2-5lbs into adulthood as we can sometimes get fuller around the middle ;)
Pomskies are supposed to be small to medium, sturdy, and athletic dogs not lap dogs or "Mini" but all breeders occasionally get that tiny one.. it happens just like with human children.