ΔE 10.5, fair: the same colour family, but not a straight swap. Cygnar Blue Highlight is noticeably lighter than Viking Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Cygnar Blue Highlight is noticeably lighter than Viking Blue.
The same difference applies the other way round: Viking Blue is noticeably darker.
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 Viking Blue on the colour wheel See Cygnar Blue Highlight on the colour wheel
All matches: Viking Blue equivalents · Cygnar Blue Highlight equivalents