I personally like to run 70% in Veg and 50-60% in flower and as I get closer to Harvest lower it down to about 40% Good luck!

IMO its all about ideal VPD (vapor pressure deficit)...which is a combo of room temps, rh, leaf temp, and think one more variable. Ideally, you get a scale of optimal RH to temp changes to be in ideal range so theres not more humidity in the air than plants can take, or not enough, and that stomata are operating ideally.

That said- once i found the range ideal in my room for temps (76-82 max temp swing), i found that having an RH between 50-65% in flower was where i found healthiest plants. So now its not as much a concern and i stay in those values.

couple things ive noticed when growing semi trees in organic tubs- even at 35-40% rh- can still hit pound plants all day on certain strains. Frankly IMO its more about the effort put into training/veg that results in yields. But you will notice that if you start to build plants with weight- humidity will become something you are working to control- not add....even out here in CO.

But yeah, there are many die hard tree growers hittin weight that swear by 70-80%...i believe they have plenty, but at a point a plant can only absorb so much and some is excess. But like i said, most folks growing big trees are dealing with rh, not adding.

what he said.