Ol photone never done me wrong yet
my paper diffuser is a loop of paper with a piece of tape on it, when I need it I just slide it over the top of my phone and hang it back up in the tent when I’m done
Was considering picking up a apogee meter but can’t justify spending the money on it over other grow materials especially when I have a free version right in my hand already, 2% (for us) will make no difference whatsoever hell we’re probably safe up to 10% or more, we’re not growing commercially we’re home enthusiasts, only reason to be that precise is if you’re looking for a specific trait (light induced herming etc) or extremely detailed record keeping, but for our purposes, I’d stick with photone