> Unless your strategy is to create a photo-lab-like screen in pure black and red, or wear deep-red-tinted glasses, it’s unlikely that a pure colorshift strategy will cut out that big of a chunk of the spectrum.

I absolutely think this is the right approach. The glasses which do 'blue light filtering' which barely change your perception are clearly placebo, but a very strong redshift I think is obviously a different creature.

I have a red flashlight I use at night to read books. It’s weird after an hour I don’t really see it as red anymore, just dim off white.

Absolutely, although dark orange seems to work well enough. If you can put them on and still tell the difference between most colors, they aren't working. I use my pair for one purpose: reading in bed with a backlit e-reader. I can't imagine trying to do much else with them on, they have plastic wings to block light from the side and they're not light.

But they work.