Sorry for the possibly dumb question but is there a page which lists all the commands that the library provides? A bit like the reference section on the Arduino website? Have looked through the wiki and found much but not all (had to look at the FastLED.h file to try and figure out how to change the brightness of the whole string 
Here is a hidden gem worth its weight in gold: https://gist.github.com/kriegsman/062e10f7f07ba8518af6
FastLED.setBrightness( BRIGHTNESS );