Re: RC boost... how much
It's a totally different type of gain, so it's hard to compare.
The AC does have that tubescreamer-y OD type gain going on.
The RC just adds this SLIGHT compression, and slight glassy grit that really sounds like YOUR rig. It's like 99.99999% transparent.
To my ears, there's really very few other pedals that sound as good as the RC for a pure, clean boost with EQ options.
So in a word, NO, they don't really overlap per se, because they're so so different.
BTW: The RC works AMAZING as a post-OD boost to add compression, gain, and volume for a solo boost. incredible.