ΔE 11.5, fair: the same colour family, but not a straight swap. Russ Grey is a little darker, more saturated, warmer than Tanker Grey.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Russ Grey is a little darker, more saturated, warmer than Tanker Grey.
The same difference applies the other way round: Tanker Grey is a little lighter, more muted, cooler.
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 Tanker Grey on the colour wheel See Russ Grey on the colour wheel
All matches: Tanker Grey equivalents · Russ Grey equivalents