Doesn't the K-30 have focus peaking? That was made for manual focus lenses, so you can use that
Also, I highly recommend an after market focusing screen that was made for fast lenses. The compromise with those is that your viewfinder will get darker with slower lenses.
As for catch in focus, some people love it, which is great of course, but I am not a huge fan. You are at the mercy of the camera, when it thinks it is in focus. I am not sure about the K-30 but with the k-5, the center focus point is gigantic.