The synopsis is that there's no substitute for shutting off screens 1-2 hours before bedtime. This coming from someone who not only uses f.lux but sometimes when needing to use the computer late, will adorn an old pair of sunglasses to further cut down on light from 3 monitors.
If you want you can turn f.lux into "darkroom" modes, which inverts the display and uses only the red channel.
https://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot...
Here’s a sketch of the basic idea: https://dotcolordotcom.files.wordpress.com/2011/10/filter-sp...
My quick google image search isn’t turning up any particularly good SPD graphs of real recent LCDs, but if you poke around you can surely find some.
In the experiment you linked, they used looking through orange-tinted safety glasses as a control, because such glasses basically filter out all of the relevant wavelengths.
Not sure I’d recommend regularly using your laptop with orange safety glasses though.