Aggaros Dunes vs Warm Yellow

How close are they?

ΔE 32.1, loose: different enough that you should pick on purpose. Warm Yellow is a little lighter, much more saturated than Aggaros Dunes.

Can I use Warm Yellow instead of Aggaros Dunes?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 32). Warm Yellow is a little lighter, much more saturated than Aggaros Dunes.

Can I use Aggaros Dunes instead of Warm Yellow?

The same difference applies the other way round: Aggaros Dunes is a little darker, much more muted.

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.