ΔE 27.7, loose: different enough that you should pick on purpose. Lucky 38 is noticeably lighter, more muted than Twilight Sky.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 28). Lucky 38 is noticeably lighter, more muted than Twilight Sky.
The same difference applies the other way round: Twilight Sky is noticeably darker, more saturated.
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 Twilight Sky on the colour wheel See Lucky 38 on the colour wheel
All matches: Twilight Sky equivalents · Lucky 38 equivalents