Humidity seems OK, but still bad shedding

I'm a fairly new Ball Python owner, and completely new to the reptile world. I've had my male ball for about 3-4 months now, from a small juvenile, and he's still pretty small. He's been an awesome little pet, extremely docile, seems to enjoy being handled, and always great about eating. However lately he's not been shedding completely, leaving behind large patches of dry skin. :(

I keep him in a 10 gallon glass terrarium with aspen bedding substrate. He's got a UTH pad below his hide on the warm side, and another hide on the cool side and he uses both hides frequently. Temp is around 78 on the cool side up to 88 in his warm side hide. I don't use a tank light. I've kept the humidity at about 50%, until I first noticed the bad shedding.

I've made a few adjustments over the past month or so to try to help. I've covered 3/4 of the screen top with a large towel to reduce airflow and I mist down the tank daily with a spray bottle to try to boost the humidity. Currently it's about 60%, but he's still having trouble with his last shedding. I've given him a few soakings afterwards which seems to help tremendously but I still wonder what I'm doing wrong. Does feeding effect shedding habits? Reading around I notice some people feed their snakes quite frequently, while I'm feeding him a live hopper mouse about every 10 days.

If he's only a few months old you should offer him food every 5-7 days. When I had a bp in a aquarium I raised humidity by buying a burlap (I think it is) sack, about 10 inches, and some dried moss. You can get the sack from Walmart or any hobby place. I placed all of that into almost boiling water for about a minute just to kill off anything that may have been hanging on to it. Once cooled I squeezed the excess out of the bottom and simply placed it in the tankin the corner. Usually on top of a hide or something so it wouldn't touch the bottom to keep them from peeing on it, then hung the string out of the top to keep it upright. I'm pretty sure that will cost less than $5. I know the sacks are about $1 at Walmart. You could also use a different type of bedding that holds moisture better. I liked the look of the aspen though, and the wet sack keeps the humidity level and also saves you from having to spray all the time .