I have been following your saga somewhat. I think you may have hit upon something as to how the wedge box is programmed. I would call a deere dealer and ask if there are different "programs" or firmware that can be loaded onto the wedgebox/controller dependent on how you are using it. It may be that you need a different wedgebox (and possibly harness) for this application. I used to have a 1990 cart in front of an 1860 seeder. It was an older model set up to run on a brown box display so it didn't matter how it was programmed until I wanted to document with a 2600 display. It would automatically populate the "Implement 1" tab and I had to enter some funky dimensions to get it to halfway correctly document as whatever is "Implement 2" or beyond doesn't enter into the documentation calculations. I'm not sure beyond "Implement 1" is even documented? I ended up trading it off so I never went any further, but I just wonder if they have different configurations that are able to be programmed? I can understand that any planter/seeder is going to take precedence but I don't know why it would kick the 1770 off the bus. I would assume that they "never envisioned that" use. I wonder if a rate controller would run it? That would be secondary to the 1770.