I doubt Vegetto was 100x stronger than Buu. Rilldo was or at least around that since Goku had to increase his power that much to fight him. I don't remember how the fight went exactly. If Rilldo made Goke work for it then he would have been massively above Vegetto.
With all that being said, Baby Vegeta was stronger than Rilldo right?
Technically, this would be the weakest incarnation:
So bored at work, I couldn't help but to nitpick a little.