ΔE 9.0, close: similar, with a visible difference side by side. Flash Gitz Yellow is a little lighter than Acid Green.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Flash Gitz Yellow is a little lighter than Acid Green.
The same difference applies the other way round: Acid Green is a little darker.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Acid Green on the colour wheel See Flash Gitz Yellow on the colour wheel
All matches: Acid Green equivalents · Flash Gitz Yellow equivalents