So many touhou fans do 'the big sister has smaller breasts than the little sister' that it's become the norm, rather than the subversion it's intended to be. It's to be point I'm genuinely pleasantly surprised whenever someone DOESN'T do that.

Especailly when Satori's got the right personality for the busty wallflower type, as shown here. Give me more shy, busty onee-chans, please!