I don't understand why some call the P7M8 small. It is not. The grip is basically the same height as a full-size gun, as wide as a Glock 19 (which has twice the capacity).
The only part of the P7M8 that is compact is in the slide, which is theoretically nice for IWB carry but the short barrel/big butt balance is odd.
For a truly compact single-stack, the Kahr is hard to beat from a physical size perspective.
IIRC the Sig 225 is virtually the same thickness as the 228.
I've had several P7M8's, a P7M13, a MK9, a 228 and now have none of those. They each were unworkable for me for different reasons. (For me at least, I can see each being ideal for somebody else for different reasons.)
With the exception of the Kahr I think they're all much fatter than a compact 9mm single stack should be.