An eighth ounce is the step up from the ultralight 1/16, for when there is current on the reef and a lighter head simply washes out of the slick before it reaches the fish.
Chartreuse is the visibility color — the one to run on overcast days, in green water, or when the slick is deep enough that natural tones vanish.
Still light enough to drift naturally. On yellowtail, the lighter you can fish and still hold position, the more you catch.