Adjusting my homemade fence with quite a bit of precision is not very difficult, as it slides easily and parallel to the blade of my table saw. However, it is tight enough to require a small effort to move it. So, for adjusting the fence by a distance as small as a millimeter, a few light taps with my fingertips and a metal ruler underneath can control the distance I move it. If I can move the fence with taps on one side to move it such small distances, or even smaller, one option could be to use a screw to push or pull the fence. I just need a way to turn and anchor the screw.
For the screw, I’m going to use a 6mm threaded rod. The advantage is that a complete turn of the rod causes a very small displacement. And that’s also the disadvantage because using a threaded rod to move the fence more than a few millimeters will require many turns. This was initially more of a test, but I think it will work for what I need. If I had to make it again, I would cut the slot where the wooden discs go into a V shape to make them easier to turn. Or why not turn the discs into wooden gears and put another gear at 90º on the wooden blocks with a small crank. This way, I could make the screw advance faster and be more comfortable to turn.