Blanki've been growing melons for a # of years now and i've found the "watch for the tendril to dry up" and "watch for the underside to turn a cream color" the least reliable methods of all, especially on the sugar baby variety. i've actually read in many places on the web that what little value watching the underside holds doesn't apply to this variety, due to its dark color.
the one method i have found to be reliable across all varieties i've grown is the "thump test." it does take some time getting your ear trained but once u do, it really does work. if u do grow the same variety year after year, it's a good idea to make notes as your melons reach certain milestone (when did the first blossoms appear, when did u see the first melon, when did the first melon get softball size - most important note of all, when did u get your first ripe melon). by looking at previous year's notes, i know almost exactly when to expect my first ripe melon, based on when my first melon made it to softball size this year and adding the avg # of days to first ripe melon (based on previous year's notes).