ΔE 9.1, close: similar, with a visible difference side by side. Viking Grey is a little darker than Turnbull Turquoise.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Viking Grey is a little darker than Turnbull Turquoise.
The same difference applies the other way round: Turnbull Turquoise 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.
See Turnbull Turquoise on the colour wheel See Viking Grey on the colour wheel
All matches: Turnbull Turquoise equivalents · Viking Grey equivalents