Colouredglass -absorbtion vs falloff

i am trying to get a nice coloured glass with the colour gradation working well according to thickness.there are two methods suggested -in material guide and later materials like "blurry green glass"
i feel the older method of making absorbtion white colour and varying falloff colour and power gives correct result(Glass2).while, Glass1 colouring is uniform-doesnt vary with thickness
which is the correct method?
i feel the older method of making absorbtion white colour and varying falloff colour and power gives correct result(Glass2).while, Glass1 colouring is uniform-doesnt vary with thickness
which is the correct method?