The RSL only needs to be visible from the front of the robot standing at least 3 feet away. However, you may run into an issue during inspection so if you can your best bet would be to mount a second RSL.
The RSL is there as a diagnostic, both to the field crew and your drive team. Ours is currently visible from three sides, so we’re adding a second light to ensure full visibility. (Yes, this is why I asked Q927.) (Note to self - get Veronica to add enabled/disabled to the spy signals.)