ΔE 8.1, close: similar, with a visible difference side by side. Skullcrusher Brass is more saturated than Hoard Bronze.
Can I use Skullcrusher Brass instead of Hoard Bronze?
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Skullcrusher Brass is more saturated than Hoard Bronze.
Can I use Hoard Bronze instead of Skullcrusher Brass?
The same difference applies the other way round: Hoard Bronze is 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.