I contend that a remarkably accurate weight estimate could be obtained IF there is a large database of length and girth measurements. For instance, take 1000 caught GT and measure fork length, girth and sling weigh on a certified scale. (I understand the discrepancy between actual linear length and the length over body contour). Given this data, a very accurate chart for length/girth measurements could be generated. Such data exists for northern pike and musky, which are very long, narrow fish with a wide range of body types. Some are very skinny, others fat bellied hogs. The Northern pike chart gives an estimate very close to actual weight. It's easy to test the chart-just weigh and measure your fish and see if it jives with the chart. If the data set is large enough, the estimations should be almost spot on.