Tundra Taupe vs Cryx Bane Base

How close are they?

ΔE 15.2, loose: different enough that you should pick on purpose. Cryx Bane Base is noticeably darker, cooler than Tundra Taupe.

Can I use Cryx Bane Base instead of Tundra Taupe?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Cryx Bane Base is noticeably darker, cooler than Tundra Taupe.

Can I use Tundra Taupe instead of Cryx Bane Base?

The same difference applies the other way round: Tundra Taupe is noticeably lighter, 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.