There is one important consideration to what ever camera arrangement is used. The look downs usually add parasitic drag, but I don't think that's a big problem unless it's a rocket designed for ultimate performance. But, when you are adding things like cameras, you should control spin by proper alignment of fins and be mindful of axial balance on the roll axis. If the rocket rolls and is not balanced, the coning can be more than a problem with performance, it can lead to the destruction of the rocket if the angle of attack becomes severe at high velocity. Cameras which attach to the outside of the airframe can create problems with axial balance unless they are counter balanced in some way.