Beshine.
While Chelsea can let her silly strings hold water & salt to get larger and then drain them (and it seems like she'd rather drain them than let them get larger), Beshine has a massive amount of cubic centimeters in her expanders, and she keeps wanting to push them larger and larger. Because Beshine has booby greed and Chelsea doesn't, even if you can isolate a moment in time where Chelsea looks bigger, she will inevitably be surpassed by Beshine.
To put it in the terminology of financial markets, Chelsea is Microsoft and Beshine is Amazon!