Back in the late 70's when I briefly worked for a DC10 operator I came across a file of newsletters produced by Douglas (I think they were titled "Know Your DC10" or something similar). One of them discussed the reason for nosecowl strakes which was as described in depth in several earlier posts (disturbed airflow off the nosecowl in the landing configuration interacting with the gap in the LE slats for the pylon was going to result in missing their target landing distance due to too high a reference speed). According to the article they started out with a strake on the inboard side that extended from the nosecowl right across the fan cowl and then shortened it bit by bit until they established the minimum size of strake that allowed them to acheive their target landing distances. Another stake was installed on the outboard side to make the nosecowl fully interchangeanle L & R.