Most of the milligram scales only do 0.02 gn. Therefore I use the mg units. This is more than enough to sort out the deficient pellets. It is important to let the scale warm up befor use. Also I change the stand to only 3 feet. If you question the accuracy, just reweight some of the first pellets again at the end of the chore.
I use the black one: http://www.ebay.ie/itm/G-G-FC-50g-20...-/141764445181
But I would recommend one with a greater weighting platform like the CT-250.