83 degrees sound hot to me. I try to keep my girls cool in the 68 to 73 degree range. Get an ac cooled reflector and a strong exhaust fan. I have a 1000w with plants 16 to 18" from light. I'm on my first grow too.
I believe the things you tested arent going to be the problems you come across when you are trying to do it right. Why not learn from trying to do it right, than causing problems that you know you are causing(easier to fix), than the problems that are going to arise in your next grow.
Foilar spray five minutes before the light goes off my experience has been if you spray while light is on plants dont like it. Which i think is true in nature too. My outdoor girls get a natural foilar dew mist at night. It evaporates before the sun is to warm.
Also OG kush might not react the same as the strain you are growing now. Good Luck
Im growing herijuana, lost coast OG, tangerine dream, laughing buddha, BCN diesel, Big Band, and a seed mix from HG Three weeks into flowering and WOW so pretty