OK, got it figured out thanks to everyone's help!
In case anyone else is struggling with this, here are some photos to help clear things up. I ended up needing an 8" long #2 Philips screwdriver.
If you look down this slot/hole:
You will see a small funnel shaped hole. Gear teeth may be visible inside the hole. Two different angles for clarity:
Actually adjusting the headlights took 5 minutes. Park 25 ft from a flat wall, mark center point of headlamps on the wall (or in my case use a laser level), and then adjust headlamps one at a time (block off the other headlamp so you can clearly see the cutoff line of the lamp you're adjusting).