
There is no such thing as a minature chi. (coward can't remember correct spelling ;) )
Some will adhere more closely to the breed standard re size than others! It is like with Yorkies and Cavaliers. I have often seen so called Yorkies the size of a Jack Russell or Cairn :D and Cavaliers that are nearly the size of Springers :D
If you see the parents it will give you a rough idea of the pups expected size. If you contact a breed club, any members that you are likely to be put in contact with, are likely to be breeding with the breed standard in mind!