I've shot 9mm and 38 Super out of my SIG Match Elite that left the factory as a 9mm. Barrel and recoil spring is the only difference since 9mm feeds perfectly from my CMC 38 Super mags. I haven't touched the extractor because function is great and I don't wanna screw it up, but it's probably a little tight on the conventional 38S brass.
I remember when you were working that out. Glad to hear you got it.
My favorite load is a case full of VV N105 compressed by a 124gr Nosler Sporting Handgun. It's running a touch over 1400 and has proven to be pretty lethal. On bowling pins.