That's general guidance for beginners. If we want to get even more precise, 82F leaf surface temperature and 54-60% RH (according to Pulse VPD chart for flower).
Edit: The reason why that's not in my book is because if you don't have excellent air circulation and exchange then powdery mildew and bud rot can occur. It seems like once a week someone contacts me telling me they tried for VPD and got powdery mildew 😕
.png)
According to Mr. Growit's book, RH between 30-50% and temp at canopy 65-80F.
Flipping is usually done anywhere after 3 or 4 weeks, but can be strain dependent