On cuttings I have in clear cups like you have I also strive for humidity in the 70-80% range!
And I would also add I NEVER just pour water on the potting medium!
I use an old printer ink refill syringe to put the small amount of water that is required for new cuttings, I have holes in the bottom and in the sides, I just put the syringe full of water(10ml) right in the area of the roots.
Others might do it differently........Good luck.