The P30 is an awesome sidearm! I carry mine frequently. But if you want something a smidge easier to conceal you might try a P2000. It gives you 90% of the capability in a package that's a fair bit more concealable due to the slightly shorter grip. It's still large enough to get a full grip on. The P30sk is another great option and one I don't have yet.

Carrying two mags is gonna be a challenge! I carry a single spare mag in a Safariland 123 Horizontal Mag Pouch. Very comfortable, easy to hide and unobtrusive. IMO it doesn't look like a mag pouch which is a plus.