Pallid Wych Flesh vs Sand Grey

How close are they?

ΔE 7.9, close: similar, with a visible difference side by side. Sand Grey is more saturated, warmer than Pallid Wych Flesh.

Can I use Sand Grey instead of Pallid Wych Flesh?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Sand Grey is more saturated, warmer than Pallid Wych Flesh.

Can I use Pallid Wych Flesh instead of Sand Grey?

The same difference applies the other way round: Pallid Wych Flesh 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.