It is possible, but will take many generations. Work is already underway to create smaller albino and other morph retics by using dwarf retics. It is going to take awhile before the results are seen. And remember, the genetics of the larger parent can play just as much a role as the genetics for the dwarf parent, so the babies will not necessarily be dwarfish per say. It will take breeding back to dwarfs to eventually make guaranteed smaller snakes.