Well, you've started something there, haven't you.
So what was the original colour?
You're going to want as good a finish as possible, I'd get a polishing machine (£50-ish new) with a big fluffy bonnet, and first off use your thinners on that to get the green off. You've got a lot of area to cover, hence the machine. You'll possibly want gloves with an area that big, or your arms will go numb pretty quickly!
Then I guess- and it'll take a while! replace the polishing bonnet and use cutting compound, T-cut style stuff. There's undoubtedly more aggressive stuff out there that might well be worth looking into.