Quote - I suppose the “Orbit” parameter dials will be what to use for pointing the angle of the camera downward at the figure’s chest, but when I use the X Orbit dial set at either 104.5 or -104.5 degrees, it is too extreme of an angle. I’m guessing a setting between -15 and -20 degrees might be more what is needed.

In Poser when a camera is at zero rotation on all its axes, it is looking straight down the world z  axis, from +z looking towards -z. If you xOrbit the camera 90°, it will be looking straight up, and at -90° it will be looking straight down. In a diffrent app, the camera bay have a diffrent starting angle, try adding or subtracting 90° from the value your friend quoted.