I use a small hand held concave vanity mirror and reflect the overhead light into my eyes. I wiggle the mirror handle to increase the spread. This is done while brushing my teeth since my electric toothbrush has a 3 minute timer.
Ergonomic ? yes. Practical ? for me yes. Safe ? maybe given the persistence effect matches what the paper said should occur. The Oxford paper used a small handheld red LED flashlight purchased for around $10 with a paper diffuser. I didn't enjoy doing it that way and stopped after a few attempts.
LCD display red should be pretty close to 670nm
https://www.amazon.ca/HIGROW-Flowering-Fruiting-Spectrum-Enh...
Here is a very informative sight which goes over how to make several different led grow light builds ranging from 2x2 foot grow tent to an led for a 5x5. https://ledgardener.com/diy-led-strip-build-designs-samsung-...