You all know I am going to chime in here, every season at every home, every bator, is a bit different, some with fast fans some slow fans, some bators hold humidity some dont, I personally hate saying dry incubation because people think that's exactly what it means. Example here, if I use a styro I need to adjust humidity differently than my cooler bators, and then differently in the cabinet cooler bator. And some people with big wooden cabinets with big fans fight to keep humidity in them.
[COLOR=FF0000]Humidity is NEVER a set number be it HIGH or LOW,[/COLOR] humidity is ONLY a tool to get the best possible weight loss in the eggs for the eggs to be viable at hatch. NO ONE and I mean NO ONE can tell you what that egg needs, it varies with what breed egg, what size egg, how old, ect...... NO ONE except you, be it by watching air cells or weighing your eggs, HOWEVER even weighing eggs you have to be careful, because shipped eggs have already lost tons of weight, and eggs sitting for a week or two already lost weight.
The more you incubate the better we become at eyeing up our air cells. The worst cases I have seen with incubating is too LOW temps and too much humidity, but that doesnt mean no humidity, your getting it from the humidity in your home or your adding water. Its up to each hatcher to figure out what their eggs need humidity wise.
Example, if you watch some of the vids from commercial hatcheries they run a much much higher humidity than we would, why? they have huge fans running in those rooms which dry out the eggs at a faster rate without added humidity and most times they set fresher eggs than we do.