Dawnstone vs Green FS34102

How close are they?

ΔE 9.9, close: similar, with a visible difference side by side. Green FS34102 is a little darker, more saturated than Dawnstone.

Can I use Green FS34102 instead of Dawnstone?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Green FS34102 is a little darker, more saturated than Dawnstone.

Can I use Dawnstone instead of Green FS34102?

The same difference applies the other way round: Dawnstone is a little lighter, 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.