Commando Green vs Arachnid Green

How close are they?

ΔE 7.6, close: similar, with a visible difference side by side. Arachnid Green is more saturated, warmer than Commando Green.

Can I use Arachnid Green instead of Commando Green?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Arachnid Green is more saturated, warmer than Commando Green.

Can I use Commando Green instead of Arachnid Green?

The same difference applies the other way round: Commando Green is more muted, cooler.

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.