If you don't want an extreme blue but more lighter this is the color for you. IT IS NOT A PASTEL COLOR so if you're going for that pastel look this is not the dye for you. I didn't have an issue putting the blue over the pink so it didn't come out looking purple (in the areas where it was still pink). For blue dye, this is the one I'd recommend hands down. It's always even and the color comes out really good.
My hair wasn't super white when I put it in so I wouldn't worry about it turning green later. I've honestly never had the green problem with the blue but actually with the purple dye. But it wasn't a big deal because it was like a hue of green but not like green green (if that makes sense). The only one that turned green for me was the Aqua in this brand. It started off as a nice teal color but the more it was washed the more green it turned. I haven't played with any of the lime green colors but I'm almost tempted to try it.
I didn't make a big deal about sectioning off the hair in terms of wrapping it in foil just let it hang. I think once a section of hair is dyed it's protected against the other colors. At least from my experience, I can't speak for others.
Check out videos with this hair: