Cut a hole in the trunk

I’ve got a couple of hours to spend on the car today and the next step is to cut the trunk for the rear battery rack. I measured the distance between the frame rails and it’s 28” - should be enough room for 5 batteries. Since you can’t really see the edge of the frame rails from the trunk, I used a drill from below to mark the corners of the cut. Using a metal ruler and a sharpie I marked out the area to be cut. I used a hand grinder with a cutting blade a little sloppy, but I can grind out the wavy edges later.