Sonic Partial Size Modifiers

[brawlerdude93]

I've tried making Partial Size Modifications on Sonic the Hedgehog many times, but very few of his ID's, when enlarged/reduced, actually do something. These values that do work are:
Whole
Chest
Belly
Groin

I've tried making Whole larger and then reducing the things I don't want bigger, but that doesn't work either. Is there an updated list of Sonic's ID's or something? Or is Sonic just nearly impossible to PSM?