You could change the Maiming Shield for the BRB Glittering Scales so both your OBs are at -1. You could also give one of them both of those items for a -2. Also, minor question, if you need a 5+ to hit in CC, and are at a -2 penalty, do you still hit on a 6, do you need a 7, or can you not hit at all?
To your CoC question: I think you need to hit on a 7. I don't have the rule book with me right now, but that's how I've been playing.