I never thought about a hanging scale.......how about fishing supplies? Those guys weigh fish to the ounce for competitions. A hanging scale sounds great for the bulky base grains. You'd want a tare button to zero out the bucket's weight.
I had to look............wow, with the tare button you can weigh multiple fish grains, and not have to measure, empty, reset, clean three bowls, etc. I'm getting one.
http://www.amazon.com/gp/product/B000E7UJTG
http://www.walmart.com/catalog/product.do?product_id=4328456&sourceid=1500000000000003260410&ci_src=14110944&ci_sku=4328456#ProductDetail