Don't do what I did the last time I went snowboarding and end up with a bone contusion. In all honesty I would rather have broken my hip.
Parroting Kirk here, I think a purpose built AA cruiser needs to be an excellent sea boat and gun platform. That said, I really like this design, since she's more than a match for all but the ~10,000 light cruisers (my fault).
@Wes: I think that's Springsharp's doing, actually. I've noticed before that if you start with metric and go to Imperial, and vice versa, the conversion is actually very imprecise.
Why not go all the way up to the 12"/55 guns that Swampy helped develop for the old Rios? I know he planned to refit the battlecruisers with them, so the guns must be available for you to use.