The Chris Reeves one-piece range was said to be 13° per side, but a slightly rounded edge in my opinion, and even this wasn't enough for me: I think 10° per side is perfectly fine on a big knife, or on any small knife. I use 10° per side for wood chopping with no issues: It's a whole 20° inclusive: Not weak at all... 20° per side is just silly.
Gaston