Given the type of work you've suggested, I'd be looking to see if I could conceal a 12ga somehow.
Seriously, I trust the Shield as my primary CC pistol (and do carry a 1911 or a high power or a J frame depending on where I'm going and how I'm dressed).
HOWEVER, I'm just a normal citizen going about his daily routine (store, bank, gas station, work, home, fishing, walking through the neighborhood, etc.). It is highly unlikely I'll ever need to draw a weapon much less to actually use one.
You, on the other hand, have a much higher probability. I'd want as many rounds of as high power and large caliber as I could realistically carry and shoot. And I was only half joking about the shotgun. All things being equal the choice between a .45 and a 9mm is clear, I'm taking the 12ga every time.