I finally gave up and went to google and found this youtube video and this is so simple and clever
It is a 13 minute video so to cut to the chase go to 3:35 for one side and 6:55 for the switchover. I knew those threewheels had something to do with it but couldnt figure out how they would reverse the rotation. IT took me about 15 seconds of staring at it to get my dyslexic brain to tell hand to slap forehead.
I don't plan on spending $1K on these so have at em.