Brandi, there is a 3rd rear remote available for your tractor, no reason to be scabbing on any after market stuff. One of these days in all my spare time I will be putting a 4th rear remote on the 7520. I'm just going to use an electric diverter. If you only need 3 rear remotes, OEM is the way to go. If you need more, then no reason to mess with the OEM 3rd unit and just use the diverters to get as many as you need. I don't think you will be moving your light at all, or did you get another tractor? Your 6520 has the lights molded into the fender doesn't it?
On my 3215, only 1 rear remote is available

, which I have. I needed 4, I now have 4 by way of 3 electric diverters stacked together.

The grey control grip is mounted on the OEM control lever for the rear remote. It has 2 button switches and a trigger switch. :thumbsup: This system seems to work quite well.