Basically it's meant to shrink one part of the body by a certain amount then grow another part by the same amount eg decreases ass by 5 then increase tits by 5
Scene probably would be not too long but to acount for all combo or growned/shrunk body parts and as I think you hinted picking amount of change...that all would make it quite complicated project. Well if someone here would take this on...I not see nothing wrong with this idea so far ^^