I think the lighting should be as consistent as possible, so either place the lights at a distance and keep them static (if they are strong enough) or set them up with the exact same angle relative to the camera.
Photoscan doesn't need shadow detail specifically, any fine detail will do. Harsh shadows are indeed bad, because often the camera doesn't have enough range to get enough detail in the shadows (or highlights start clipping).
If you photograph a wall you do not need to vary the angles, just varying the position will do. Position variations give Photoscan more information that camera rotation.
Image quality is everything, so use a tripod and a remote release cord, and check your photos afterwards and remove the blurry ones.