[pja]

Simon Cozens spent some time writing a new typesetter called SILE:

  https://sile-typesetter.org/

On of the design goals was to be able to achieve exactly that kind of line matching. IIRC it can ensure that lines on the front & back of a page line up exactly too; apparently this is important for bibles?

Worth taking a look at. It recently acquired TeX style mathematics typesetting ability & has a small but active developer group.