I am of the opinion that you want zero light leak or lights from inside the tent during the dark period for photo period plants. Ideally you want to condition the room that your intake comes from as opposed to conditioning the tent. This doesn’t work for me so I deal with the humidity and focus on air flow. I have read enough Hermie threads on this site that trace back to power strip indicators, humidifiers, dehumidifiers, etc. to scare me away from messing with that. I have no personal experience with it because I did this reading before flowering my first plants. I have abused them though ( temp swings, humidity swings, aggressive defoliation, supercropping a month into flower, etc. Etc.) and no Hermie issues.