Radiation Glow vs Meaty Ochre

How close are they?

ΔE 20.4, loose: different enough that you should pick on purpose. Meaty Ochre is noticeably darker, more muted than Radiation Glow.

Can I use Meaty Ochre instead of Radiation Glow?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Meaty Ochre is noticeably darker, more muted than Radiation Glow.

Can I use Radiation Glow instead of Meaty Ochre?

The same difference applies the other way round: Radiation Glow is noticeably lighter, 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.