Which ASL gloss represents the most conceptually accurate interpretation of burn the midnight oil?
This is a subjective question as ASL gloss can vary across interpretations. However, a conceptually accurate gloss for "burn the midnight oil" in ASL could be:
MIDNIGHT OIL B-U-R-N
Note that in ASL gloss, the letters are capitalized to indicate fingerspelling, and hyphens are used to indicate separate signs. Keep in mind that ASL is a visual language, and the gloss is just an approximation of the signs used. The best way to fully understand the concept of "burn the midnight oil" in ASL is to observe native ASL users signing the phrase.