I just wanted to share my experience with https://www.shuttleslide.com I'm not affiliated with them in any way but did just use their product for an installation and was very impressed. They were very friendly on the phone and have a pretty neat slide mount that can help with complex trolling motor mounts. In my situation, I simply wanted a way to pull the motor back so that my navigation light would not reflect off of the head. They also have adapter plates so that you can switch trolling motor brands or add their slide without adding any new holes to your boat.
Anyway... just wanted to mention them for those who didn't know about the product.