just give them a humid hide on the warm side.the humidity in my tanks are around 20%.i give them a humid hide and they shed great.i know people will disagree but ive been to vets,showed them my snakes and gave them info on my tanks and they both said the snakes looked great and to keep doing wat im doing.yes it is best for the humidity to be at least 50 but as long as they have a humid hide(wich is where they spend 90% of the time,you will be fine.

hope this helps ya!