Thank you Brother!!Run a piece of tape vertically from each hole under the bed so that you can see the tape with the liner installed. Make it an inch or so longer so that it hangs beneath the liner when installed. Mark where the liner hits the tape when installed, and place a mark on the liner where the tape hangs down. Remove the liner, measure the distance from the center of each hole, to the mark you made on the tape. Once you have that length, measure up from your marks on the liner, and drill your holes.