the ripeness can be temperamental, to the point to the professional growers I visited in southern Thailand would label and date the fruits after pollination. Then they would keep records and compare to see which stage is best for harvesting. Even so, each inflorescence will still vary in flavor as fruits can have 0-3 seeds, those seeds affect flesh and flavor as well.
Then the big flavor killers is after they harvest they flavor degrades, to the point where they are still edible but have a musty mushy sweet flavor.
Then.. finally, you have many different genetic varieties, and species, with flavors like sour lemon, plain apple, pineapple, etc.
Anyways, there is my 2 cents, Sala is one of my favorite fruits! Plus the branches can be laid down and stacked to keep out animals and people!
Just spent some time in Bali Indonesia and this fruit was given to us by our resort (middle one)
They called it snake fruit because of the skin. It was a very hard skin, but soft texture inside.
Wasn't too sweet... and just tasted 'ok'