If your goal is strictly to get smaller dogs, then you are already starting off on the wrong foot.
That is a practice that only shady BYBs and millers tend to practice, not reputable breeders. Reputable breeders strive for healthy dogs, free from genetic issues that are quality representations of the breed. Anything else and you would just be striving to become BYBer #73,853.
First off, before you actively try to acquire your dog, you need to find a breeding mentor who will help guide you and even select your breeding stock. (Think about it, how are you going to go about selecting quality stock if you don't have the basics down first and have no idea what you should *ultimately* be breeding?)