Light pink to green

Not sure if this belongs here, so apologies if this is the wrong board. I've also been looking around here to see if any of my questions have been asked before and couldn't find any. If they have, please point me in the right direction.

I've had pink hair for going on 11 years now (with some years of variation) but I've been really itching to try and get my hair dark green. The pink is a mix of SFX Atomic, cupcake, a small dash of MP turquoise and a lot of conditioner.

I know that pink + green = brown, so I've been fading my pink to as light as I can. It's been almost eight weeks since I dyed my hair pink, but it's still a pastel pink.

Here are my questions:

-What brand of green is best/long lasting? I looked for some answers about green dyes and couldn't find any. I bought a bottle of SFX Iguana Green for my niece over the summer so I have that on deck.

-I know that I will eventually want to go back to pink, so I was wondering what success people have had going from green to pink? Like, how long did it take? I refuse to bleach out color since I am also in the process of growing my hair out, so I do not want to damage my hair. If I hear that it's impossible without bleach, I'll abandon this mission.

-my pink is currently fading a cool pastel pink, would a blue-based green help with the eventual fading from looking too icky brown? Or is that something that really cannot be helped?