That's pretty easy on paper, but I should preface this with the fact that this is hardly a rigid definition; there are always going to be exceptions and outliers simply by virtue of the fact that every single Stand is different. That said, I see it as a scale:
-Largely independent Stands, possessing a voice and will reflecting their user but also separate from them (Spice Girl, Sex Pistols) -Somewhat independent Stands, reflecting their user's will but with the capability to act for themselves (Star Platinum, Silver Chariot, Gold Experience) This one is what I think the majority commonly fall near or directly under. -Stands lacking independence, either a complete manifestation of their user's will or simply lacking one of their own (Hierophant Green, Hermit Purple)
no subject
-Largely independent Stands, possessing a voice and will reflecting their user but also separate from them (Spice Girl, Sex Pistols)
-Somewhat independent Stands, reflecting their user's will but with the capability to act for themselves (Star Platinum, Silver Chariot, Gold Experience) This one is what I think the majority commonly fall near or directly under.
-Stands lacking independence, either a complete manifestation of their user's will or simply lacking one of their own (Hierophant Green, Hermit Purple)