Hey friend,
Usually more light is always better as long as it's not over heating and burning them...but theres always a max amount of ppfd a plant can handle and it varies plant to plant.
I would do the defoliation once you see pistils forming, right around the 1st week of flowering. And it should do a nice boost of growth when flowering starts. I also think defoliating the bottom, is best..if you don't want a bunch or popcorn buds.
Also any chance you can get the heat down a few degrees? Maybe 78-80?
And this is just personal opinion...but I think all living things benefit from sleep or rest...maybe taking your light hours down to 20/4 versus 24 hours would give a little relaxation and lots of plants do an amazing amount of growing during their dark hours. Just a thought.
Good luck with the grow. ✌️