2015 Chevy (Holden) SS, 1989 Milano (Shankle Sport), 1991 164S
In that pdf, there is a photograph of the top of a sender, with a green dot indicating where the hole should be drilled to relieve pressure inside the sender can. That green dot is shown on the wrong side of the top of the can. The drill location should be on the opposite side from the vertical groove in the can, whereas the photo shows a green location dot adjacent to the groove. The internal mechanism is inside the can under that erroneous location, so you don't want to drill there. The can is empty on the other side.