It's a complete guess without magnification and observing state of trichomes.
you'll want anywhere from 10-50% or more amber -- you can read about the varying opinions on how that impacts the buzz simply enough with google, so i won't bore you.
if you can't zoom in, i'd suggest this... when it looks ready, wait another ~7 days, lol... at least. If a bit anxious, wait 14 days, because you are likely biasing your observation :P that's half a joke.. but likely wait longer than you think.
but seriously, get a cheap scope for $5-10 on amazon, or spend a bit more and a get a digital microscope which can give a much wider field of view... nice to use in this functions, but I think it's more for fancy pictures.