There was something lacking from my first attempt at the sefadu - the red was too dark, and I wasn't completely satisfied with using the yellow as an extreme highlight.
So I gave the red a few thin coats of Blood Red, highlighting up with each coat. I'm not sure if the photos show it clearly, but the yellow I used for the extreme highlights are still faintly visible, which I think does well to add to the overall blended highlighting.
Without the yellow though, the colour scheme was missing a bit of pop, so I painted the backpack fins yellow for good measure.
Here are some comparison shots of the red and yellow highlighting:
I'm happy with my sefadu colours now, and am ready to get to work on the rest of the squad!