Hi, if the hood has no way for ventilation yes you will have to change it for the screen top. Your humidity is good but you can let it drop to around 70-75%, I keep all mine at 75%. This way when you mist it doesn't shoot up past 80% for to long, if kept in anything over 80% for long periods of time it can lead to fungal or bacterial infections and even respiratory problems. If you find your losing a lot heat and humidity you can cover half or a little more of the screen top with foil or saran wrap to help keep it in. Your heat can come down in that warm end back down to around the 83f mark that you had and have the opposite side of the tank a few degrees cooler, this way he can thermal regulate his body temps. The highest the heat in the warm end should be is 85F, and from what I have read and seen a lot of people keep it around 82f to 84f. If that UTH is on the bottom you need to have a probe right against it under the substrate to know what the temp is, if its 86F above ground its going to be around 90f or more by the glass and this is way to warm. Something to remember is that these guys bury to cool off. Not saying to not use the UTH if this is the only way to get your temps right, its just something to consider if you can get away with not using it.. For night time what your doing is what you would want to do, you want the temps to drop a few degrees and this should trigger him to come out and eat. For the eating some are way more fussy then others so just keep trying, when are you feeding him? The best time to feed is at night an hour or so after the temps have dropped, and try to have as little light in the room as possible. If your tong feeding try rubbing it under his bottom lip, sometimes this will trigger them to eat. I think you already mentioned you covered some of the sides but if not covering 3 sides of the tank helps and if not already try to have his tank somewhere in the house that has low traffic, they get scared and stressed pretty easy.