The brakes have two anchors. Use the one without the set screw. I know that is common sense, but I am trying to be as clear as possible here.
Drill out the existing hole with a 4.2 mm drill. I know metric drills are hard to come by. You can also use the next smallest decimal equivalent, which is a #20 (0.161")
Tap the hole with a M5 x 0.8mm tap. This is the same tap size as a water bottle boss.
You can use adjusters from Shimano down tube cable stops, such as the CS50 here. Campy adjusters do not work because the thread is too fine.
Thread in the adjuster and set the brake for your widest rim. That way, when you switch wheels, you can take out the slack. This is very handy when switching from Reflex rims to something else. The Reflexes are a couple of mm wider than most other rims.
It's fast, easy and a great time saver.
