Warm Orange vs Orange Rust

How close are they?

ΔE 7.2, close: similar, with a visible difference side by side. Orange Rust is a little darker than Warm Orange.

Can I use Orange Rust instead of Warm Orange?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Orange Rust is a little darker than Warm Orange.

Can I use Warm Orange instead of Orange Rust?

The same difference applies the other way round: Warm Orange is a little lighter.

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.