ΔE 8.8, close: similar, with a visible difference side by side. Ghost Green is a little lighter, cooler than Forest Faun.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Ghost Green is a little lighter, cooler than Forest Faun.
The same difference applies the other way round: Forest Faun is a little darker, warmer.
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 Forest Faun on the colour wheel See Ghost Green on the colour wheel
All matches: Forest Faun equivalents · Ghost Green equivalents