VPD changes by plant?

[narmohare]

Hey guys, I was wondering how you deal with VPD when you have plants at different leaf surface temperatures. For example, one of my plants has a leaf temp of 72, while the other one has a leaf temp of 76. I've been using some CHARTS (near the bottom of the page). According to the charts, if my leaf temperature is 5 less than the environment (77), then the optimal humidity would be 40-50%. However, if the leaf temp of my other plant was 76, 1 less than the environment, the optimal humidity would be 60-70%. So how do I account for this? Split the difference and aim for 55%? Also what temperature range is it really safe to use when dealing with autoflowers? Currently growing in my basement, and during the lights off period my grow area can get down to 62F. Is this way too low? My lights on temp is usually about 70-72, but can get a few degrees higher. I've seen people elsewhere saying they always keep temps at around 80 during lights on, and 70 during lights off, is that more realistic? Will I have slower growth at my colder temperatures?