I can't estimate weight for sh*t. I always think they're bigger. Grab a scale for 15 bucks. It won't take up a lot of space and it adds a little excitement when you catch a hog and hook him up. I caught a 4.14 the other day. If I didn't have a scale I would've called it a 5 pounder. I know 2 ounces isn't enough to tell the difference by looking at him but knowing for sure is keeping my in pursuit of my goal. a 5 on the scale.
9.4 was only 22 inches long! Plus everyone should have a scale when your in a tournament for when you have to cull. Every oz. Counts how would you know which one to throw out of the well? Remember its the best 5. Our last tournament we culled a few times, gain a few oz. Each time, hard to tell the difference between 13 oz and 15 oz. Do that 3 times that's half a pound! Could be the difference between 4th place and the $$$$
Those charts are just a basic way to estimate a fishes weight. All fish are built different some are long and lean some are short and stalky. The last 2 "big " fish I caught were 5lbs and 6.2lbs. The 5lber was longer then the 6 but the 6 had much thicker shoulders.
A lot of people dont use a scale, but everyone has a calculator on their phone. A decent way to guestimate weight without a scale is length x length x girth / 1200.
Example:
L 20 X L20 =400 X G 16
This gives an answer of 6400 to divide by 1200 which equals the weight of 5.333 pounds.