I installed a strap button on the treble side of the heel of my acoustic guitar’s neck. I based this on a bunch of reading (here’s my favorite article on placement, and another here, here, and here) and looking at a bunch of guitars that had strap buttons on the neck heel. I quickly realized I don’t like the strap button on the heel cap and I didn’t want the button to interfere with my playing on the upper frets of the guitar. So I put it in the middle.
I placed a piece of tape and marked the spot I thought it should go. I used a piece of tape folded in thirds to hold the button in place and then played something on the upper frets. It seemed ok, so I drilled a hole that was just smaller and shallower than the screw for the strap button. Then I ran the screw against a bar of soap and screwed it in with a screw driver so I could feel when I needed to stop. It went right in.