Optimum humidity with Co2?

[Kronikal_kiwi]

Hey there

I have been told today that if supplementing a grow with Co2 you should also use higher humidity (65-70%). Apparently the higher humidity opens the plants stomata and allows more absorption of Co2.

Is this true?
If not what is optimum humidity?

 

[LeafLady]

We like to run things a bit dry. Around 50 - 60% humidity when flowering.