This can be done with a great deal of care. You need to use a “Level First” approach. You cut on both sides of the thin wall, then move down to the next cutting level. If all cutting conditions are nearly perfect, you should be able to get either aluminum or acrylic pretty thin. (0.005"). This also depends on the depth of the cut too.
That being said, why not cut the letters, fill them, let that harden & go back & cut the strokes then fill them? Then you don’t need any thin walls.