As Paul says, short shotguns aren't that narrow. Looking at your photo I would suggest 2 or 3 across the rear bar, angled fairly steeply down away from the stage &, if possible, do a band-only rehearsal, adjusting the mic angles for minimum band pickup. You won't cover the whole congregation, but nor will you pick up individuals, unless only a few actually sing, in which case you have a problem anyway! If the congregation sound a bit "thin" try adding a bit of Chorus Fx (Ok, it's a cheat, but then sound balancing always is).