defoliate mate..remove most of them bigger leaves
and if you have speed controlled vent and it isn’t all ready running 100%, blow it up to 100%.. or maybe turning that oscillating fan on high level
My intuition told me that 60 would be fine as long as you have very good air exchange, it just makes sense, as long as you dont have stagnant air you should be okay, in theory.
im not seeing other options..although your grow looks great 🤘🏽