if you want to get more off the plants, you have to get them bigger before you flip them to flower. figure out how big they can get in your cab, then veg them till they're about half that size. get a couple of 5000K bulbs to veg under, and then switch them to 3000k when you start flower.
the size of your pot directly effects how big your yield will be. when i started off i was using 3 gallon smart pots, and would get maybe 60 or 70 grams dry off of a plant, went to 5 gallon hempy buckets and am getting 100-150 off clones of the same plants, grown to about the same size. i just started using 20 gallon totes for a couple of plants, and i fully expect my yields to jump up over 200 grams dry per plant, hopefully more. more roots = more fruits, for real.
those temps are going to kill you. unless you have a closed system running CO2, you don't want your temps to get much over 28C, it really slows things down, makes the plant work a lot harder for no end return.a cool mist humidifier and a small fan will help, may drop the temps by as much as 5 degrees, and the plants usually like the higher rh, as long as pm isn't a problem