Congrats on the new sidearm - HK7, that is a hefty gun for pocket carry. :-) however, it’s rather unique and a certain attention getter at your neighborhood range.
I’ve got one of those slip on grips as well, handy little dickens, and resuable.
Only the little Beretta Tomcat is small and light enough for pocket carry, but it's the only one so far that has passed my holster and function tests. Everything else will have to hang from my belt.
So now my two top candidates are the Sig P239 in .40S&W and the HK P7PSP in 9mm. Both happen to be single-stackers, and both have single unambiguous modes of safing and firing. I want to make everything as foolproof as possible, even for myself.