> Lilypond handles slanted Beams in a geometrically weird way, that > is, the thickness is not measured as the shortest distance between > the opposing sides of the boundary, but as vertical distance. This > results in Beams getting optically thinner and closer the higher the > slope is. But we can very easily factor this out by adjusting the > thickness to the slope. In fact if we want to achieve a real > thickness theta the adjusted thickness would need to be > theta·sqrt(1 + slope²). See attached an experimental example.
Looks good! However, I don't fully agree with the thickness values in your experimental example. For very steep angles the beam appears a little bit too thick IMHO; I think there should be a correction factor. Werner