I'd say that no it is not enough. The real test is will it smell musty or old after a week or so. Closed feeling. Controlling humidity in this way is unhealthy, using the moisture of exhaled breath is not a good option. Building a petri dish for your snake is not a great idea. There are serious health risks associated and documented by vets and well respected breeders alike. The Barkers of VPI (very highly respected throughout the community, called as expert testimony by USARK) state...

"poor ventilation is generally undesirable, whether it is intentional, to raise humidity, or whether it is a flaw of the enclosure. Poorly ventilated cages with warm temperatures and high humidity are breeding grounds for bacteria, fungus, and molds. Ball pythons fare best in well ventilated, dry cages with moderate to hight humidity.

...

They (Ball Pythons) do not tolerate poor ventilation without suffering consequences. Keeping ball pythons in high humidity without good ventilation is courting problems of health and maintenance. This is one area which the Herp maxim, "It's best to err on the side of dry," is definitely applicable."

Ball Pythons 2006 pp40-41

There are a number of RI posts that all point back to tubs that have little ventilation, many refuse to believe this but the facts speak for them selves.

More holes are better than few, too many and too low humidity = poor sheds Too few and high humidity = health issues vet bills ect.