Nice! How did you know where to drill the hole?
If you do not have them on file, frame dimensions are on Team Camaro countless times. All you have to do is use the reference points and dimensions to locate a hole. If the frame drawing was not available, the shell could be used as reference. You'd need a drawing if you had to yank a car on a frame machine.
Upon request, I've had to cut out and repair the often damaged center section of the subframe. Put a brace inside before welding the skin back on to prevent jacking damage. Easy tasks.