Consider staying where you were adjustment wise. There is a diagram that's been bouncing around for several years - first at LF and then other places showing the vital anatomy and a plate. This is so the wearer knows how high it needs to be.
Agreed. I'm looking at VelSyst's LPAAC (or similar) rather than getting a post-retirement PC. I'm still a student and I still teach. The advantage of the LPAAC is that I get soft armor coverage - like my concealed soft armor - with the ability to add plates w/out the significantly increased bulk of a PC over the top of the soft armor.
I know there's significant concern about rifle rounds but even domestic L/E, the majority of the threat (70%+) is handguns and shotguns. Having more coverage front, back, and sides might not be a bad thing.