Found the orange too dominant in the original Overachiever recipe. It's a powerful aroma and it's noticeable even at 0,5%. When comparing to the original Snake Oil, the latter was much more acid. This recipe is much closer to the original IMO, and the extra Lemon Sicily, Sour and Citric Acid are aimed at that acidity.
The pineapple is a key element, and any slight variation in its amount changes the result dramatically. I've done tests with Grapefruit (Inawera), Apricot and White Peach (FA). Any of them can be used and all three are strong even at percentages as low as this. White Peach will make the liquid noticeably sweeter, and Grapefruit will add a bit more sourness. Apricot is right in the middle, so I put it in the recipe.
Putting this side by side with the original Snake Oil, the latter has a bit more lime, but I like it better this way.
@Dmitriy % @Andy I use citric acid from a vendor called VapFip. There is also CA from Solubarome, which I have also used successfully. Probably there is CA from plethora of brands. It is dilluted in PG, BTW.