Cotton Seeds Scale | Nancy Drew: Ghost of Thornton Hall

Find some cotton seeds:
If you haven't yet, take the bag of cotton from the right hallway upstairs.

Place the bag of cotton on the bin of the cotton gin.

Take the cotton seeds from the slot at right of the gin. Done, that's all of the seeds.
Using all of the cotton seeds, find a way to balance the scales:

Go to the scale right of the Cotton Processing door.
The cotton seeds are automatically placed on the bin below the scales.

Place seeds on the 4 scale platforms to balance the scale.

Amateur:    At left arm of the scale; place 1 seed pan 5, 3 seeds in pan 2 and 1 seed in pan 1.

At right arm of scale; place 3 seeds in pan 6.

Master:    At left arm of the scale; place 3 seeds pan 6, 2 seeds in pan 3 and 4 seeds in pan 1.

At right arm of scale; place 2 seeds in pan 2, 2 seeds in pan 5 and 2 seeds in pan 7.