Update: I retested my 1DX - 24 f/1.4LII combo using LensAlign, and it seems my original adjustment of +3 worked better than the FoCal recommendation of +12. So I changed it back. With the 5D3, the FoCal result was +7, with LensAlign giving me a +5. I'm guessing the differences are due to the extreme subtleties involved here, and my testing procedures which I'm sure are not up to laboratory standards. Most of the time I'll be using this lens in manual focus mode with live view anyway.