Bugman's Glow vs RLM 79 Sand Yellow

How close are they?

ΔE 17.2, loose: different enough that you should pick on purpose. RLM 79 Sand Yellow is noticeably darker, much more muted, warmer than Bugman's Glow.

Can I use RLM 79 Sand Yellow instead of Bugman's Glow?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). RLM 79 Sand Yellow is noticeably darker, much more muted, warmer than Bugman's Glow.

Can I use Bugman's Glow instead of RLM 79 Sand Yellow?

The same difference applies the other way round: Bugman's Glow is noticeably lighter, much more saturated, 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.