I use that same procedure for balancing my blades, except that I am fortunate enough to have found a 0.01 gram scale.
1050MM ROTOR DIAMETER
So I'm assuming that blade size is about 500mm long? As a pointer, when somebody asks you about blade size, they are referring to blade length, not rotor diameter.
And yes, a 1/2 gram scale should be accurate enough to balance 500mm blades, my question was trying to find out if you were trying to balance blades for a TRex 250 or something similar.
Rafael