Depending on your climate your humidity in incubator most likely wont maintain 30% without water. I agree with the lower humidity incubation but most people have to add water to keep 30-40% first 18 days. I use a shot glass to maintain. During lock down a small tumbler gets me to 60%. I've not played with covering part of the bottom water trays with aluminum for less humidity yet and don't have turners so by glass size works for me, size of water trays doesn't for me. You need humidity just not the high amounts some sources recommend (read of 60% then up to 75% and that's just too high). What it takes you in your climate, that time of year, your home heating source, if you use a humidifier or dehumidifier is all case dependent. There is no "dry" hatching but definitely a dryer incubation method. Majority of BYC'ers will say that is 30-40% (don't worry if it drys out for a day now and then) and 55-60% last three days. Calibrate your hygrometer with a salt test.