ZUN has personally blessed you with the power to canonically give one hu of your choice massive milky mammaries. He and the entire community will respect your choice and portray the character as such from now until the end of time. This change also comes with a sudden influx of art and an increase in the character's number of fan works (the effect is greater the less popular the hu was prior).
Do you go for the safe option and cement a protag who will always regularly show up, or do you pick a personal favorite? Do you elevate a hu that didn't get the fan attention she deserved?