I looked very closely at the Lange 1815 chrono (early and current versions) but couldn't love the case nor dial. The 5170 (breguet numerals) won easily in those areas. I thought the 5172 dial was unnecessarily large and thought that size might not age well. I went with the 5170R-001 for the dial, case design, and smaller size (though the opaline dial wears larger than the 39.4mm size.
Best,
Robert

5170R-001