Do humans squint more readily at green light?
Yes.  According to Action spectrum for photophobia Journal of the Optical Society of America A, Vol. 20, pp. 1852-1858 (2003), the most squinting-sensitive wavelength is ~510 nm, which is green.  Squinting sensitivity progressively falls above 510nm, and below 510nm squinting falls to a local minimum at 460 nm, and then rises again below 460nm, but did not reach a higher maximum in the range studied, which ended at 420 nm.