Enjoy your new 9C. I love my 40C.
I figured what to do with the area where the palmswells are kept in the case. I only need the one that's on the gun & keep the 2 others in my range bag. Two regular magazines fit in there nicely & after the extra foam is taken out of the normal mag space a couple of FS mags fit in there. I put the extra foam between the compact mags although that's not necessary.
The case I have for my FS M&P40 is nicer. It's black, the foam is stiffer & keeps its shape better while offering more support for gun & mags.