Fluorescent Orange vs Bile

How close are they?

ΔE 106.1, loose: different enough that you should pick on purpose. Bile is noticeably lighter, more muted, cooler than Fluorescent Orange.

Can I use Bile instead of Fluorescent Orange?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 106). Bile is noticeably lighter, more muted, cooler than Fluorescent Orange.

Can I use Fluorescent Orange instead of Bile?

The same difference applies the other way round: Fluorescent Orange is noticeably darker, more saturated, 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.