I just went through this yesterday, I ran a piece of masking tape from the e-brake cable hole in front to the spot in the rear that the cable runs through. That gave me where the slots had to be cut. I marked where those spots were on the frame connector then took a grinder and ground slots in the frame connectors so the cable can pass through.
It didn't take longer than 10 minutes but now I have to repaint them because of paint burnthrough.

Sheldon