I have found the same issues with you regarding the seed sensors.  I have part of my planter running JD optical sensors and part running WaveVision sensors.  The WaveVisions are indeed better at counting sorghum but still aren't perfect.  I created a new crop configuration in my 20/20 with looser tolerances so the alarm wasn't going off all the time.   Regardless of what the sensors say, expect a good stand unless your singulators are worn out or you are running too much or too little vac.  The eSet sorghum plate will picket-fence milo just like corn.   I have no idea about canola, but as far as I know, the WaveVision sensors are the best available.

The eSet sorghum plates are very sensative to singulator wear.  As the singulators wear, they get increasingly aggressive at knocking seed off of the holes.   To check the singulators,  you have to check them with a corn disk.  The last lobe of the singulator should cover no more than half the hole in a corn disc.  You should run 11-12 inches of vac with the eSet sorghum plate and should use a "specialty extractor".  Do NOT run the corn extractor with the sorghum plates or it will cut a groove in them in a couple hundred acres and they will have to be replaced.

If you are running seed treated with insecticide treatment, the treatment will build up on the seed side of the sorghum plate pretty fast.  I premix all my sorghum seed with enough 80/20 talc/graphite to turn all the seeds gray before putting it in the planter to avoid this.