Here is what worked for me:
- Get 6 cheap screws of the correct diameter (3 for each side).
- Grind the heads off the screws to obtain a tapered point at the top of each screw.
- Screw the screws into to the holes, leaving them out a little.
- Put the headliner into place and press the headliner onto the tapered screw-heads. Remove the headliner, drill-out the screw holes, and cut-out a hole between the three screws (so the pivot in the visor arm).
- Install the headliner and screw-in the visor arms.
- Have a beer or a cup of tea and admire your work.