Yep, more holes are called for - maybe two rows on the sides and a few in the lid. That's what I had to do for my tub and now the humidity is always around 55-60. If it goes up, then I know I have a mess to clean up.

But yes, give the snake that whole week to settle in before trying anything, be it more holes or feeding. The important thing now is to make them feel secure in their new home.