EUV values vary by 30 - 100 % across
the range over the solar cycle, and have the most potential to modulate atmospheric chemistry, size and temperature.
In that context, I find the results of Shaviv particularly interesting with their cosmic ray link: Shaviv (2005) carried out a similar analysis for 6 different time scales,
ranging from the 11 - yr
solar cycle to the climate variations
over geological time scales.