Does anyone either know the dimensions, or where to find the dimensions of the square cubby hole where the trailer brakes would go if you had that option? I'm putting in rocker switches and need to make a insert into it to allow more then 2 switches, I just really suck at figuring out radius of corners

 

Just went out and took a measurement for you, I got 2 7/8 x 1 3/4 (edge to edge where aluminum cutout is)