My master light sensor and a few others are reading off the charts, up to 117%! Is it normal for my sensors to exceed 100% light level?

Yes it is normal, as long as you left Daylight Harvesting at default of 50%! 117% isn't high because it is what the graph is calibrated at. The graph is showcasing daylight harvesting working perfectly! However, if all light sensors are reading this high, you might want to tune your calibration.