The  grid on the right side of the combine has  a wire grate that will allow a lot through without plugging.  In weeds , the rest of the rotor plugs up to a degree.  Iknow the grain screws through and cannot get out.  Case-IH in the early 1480 s had a solid sheet under the bottom of the  beater at the end of the  rotor  to flip the strow to the spreaders.  I changed it out for a wire grate unit out of Canada and could see an improvement  in less grain lost.    Gleaner rotors need that second wire grate at the left end of the  rotor  to allow more  of the grain to drop out rather than be tossed out with the straw.  It might increase the  trash over the shoe, but I would be interested in  seeing what would happen. I now have the R62 and enjoy the job it does except in heavy green weeds.  I do wheat in Oklahoma.  I am a farmer.   Sorry  I'm late replying.