How would you add two more lines of your own to the captain's song in Treasure Island?

Billy Bones is singing a sea chanty, a rhythmic work or drinking song. In this case, it’s drunken accompaniment to his odd comings and goings. As he is a mysterious character, Jim can’t help but sift through it for meaning, as the motley presently-sea-going crew members must analyze the treasure map inn hopes of uncovering its meaning. To lend some context, Jim narrates, “At first I had supposed ‘the dead man’s chest’ to be that identical big box of his upstairs in the front room.”
But the song is more of an appropriation of a traditional tune as the old captain’s aural signature; later in the book, a snatch of the lyrics is used to represent the captain’s "dead hand"—his continued, post-mortem influence.
It goes:

Fifteen men on a dead man’s chest
Yo-ho-ho, and a bottle of rum!
Drink and the devil had done for the rest
Yo-ho-ho, and a bottle of rum!

Therefore, in my opinion, the song doesn’t contain a clue to the treasure. It can be interpreted as a sketchy foreshadowing of doom, though. As in, a projection of not only future events, but the characters’ inability (with the possible exception of Silver) to forestall such events, owing to their own perceived stake in Flint’s fortune.
So, to continue in the vein of the song, and to forecast pending events in the plot, my additional lyric would be:

If fair-minded men are to succeed
Yo-ho-ho, and a bottle of rum!
They must master their dastardly greed
Yo-ho-ho, and a bottle of rum!