Corpse Pale vs Moonray Flesh

How close are they?

ΔE 6.7, close: similar, with a visible difference side by side. Moonray Flesh is more muted, cooler than Corpse Pale.

Can I use Moonray Flesh instead of Corpse Pale?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Moonray Flesh is more muted, cooler than Corpse Pale.

Can I use Corpse Pale instead of Moonray Flesh?

The same difference applies the other way round: Corpse Pale is more saturated, 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.