I have been using a laser crosshair to align my router bit with my work piece. This is useful for example for setting the home location to a specific spot or to perform test runs.
The crosshair is pointing exactly to where the center of the router bit contacts the work piece.
I added a small switch and a 2x AA holder to complet the setup. Examples for those are:
Some soldering of the switch, glue for fastening the battery holder on the sled and a piece of metal
I had this also on my old sled and liked it. Now with the linkage sled, I like the fastening even better.
Please let me know if you have any questions.
As always, comments are welcome.