yep we lightened it the second time around, using the stuff you recommended, but only the longer hair on top, the sides is his natural color. He actually ended up liking this color more than the original color he had planned for lol. He almost wanted to keep his hair how it looked right after it was lightened before the color was added xD but I think the pull to have green hair was too strong haha.
we have lots of extra, I even got some of the ion chartreuse color to try out once this starts to fade. It really was a LOT easier then I had originally expected lol. Once he gets sick of green I have a feeling hell be going for blue, he was eyeing one of the teal/blue colors in sallys lol.