To add, I have wonderful sheds, and all but one of my snakes are in tubs (even the one in the tank, a corn, has never had a bad shed). Might want to look into a tub setup if you don't see improvment for his shedding. Tubs just maintain humidity so much better than a tank setup, and the temps are always spot on as well in them.
Feeding once a week is fine, it just depends on what size you're feeding. I have one snake who will only take smaller meals so I have her on a 5 day instead of a 7, and all my little ones are on a 5 day as well.
Agreed with llovelace, if we know how you're measuring temps, his weight in grams, and to make sure your husbandry is good we can better help you.