Every time the F/O landed right of the C.L. I asked them how they were referencing the C.L. visually. They all said trying to put it in line with their left leg. It NEVER worked. Every time I suggested they put it between their legs they all said it was easier and also more accurate. They proved the point by thumping many C.L. lights then squeezing a little rudder to bring them a gnat's cock off the C.L. It still didn't look like their left knee was the reference. I did the same for >+10 years from both seats and it worked: B737. I guess the big boys might use legs & knees and other accessories. But then again we are talking minute fractional tiny distances and and not worth a bun fight about.
QED.