Gradient node questions

[dinf]

Hey,

a) do the colors and brightness tones in the gradient node have any effect on input textures, or are they for blank left inputs and the counts of them only?

b) I blended textures with the gradient, wich works nearly as expected. But blending normal maps does not show any effect. Am I doing wrong or isn't that working?

c) I took a b/w gradient to blend the tex from b), to build the surface of a landscape. In case of "touching" black and white on the driver map wich is responsible for the dispense of the input textures, the one pixel blend leads to a seam of all textures from "start" to "end". I think I understand the logic behind but have to ask, if there is a way to get rid of this seam inside of the gradient?

Thanks!