Tub inquiry ???

I have a question regarding a tub I bought. How many holes should i drill on the sides and top for ideal humidity, but good ventilation as well? Its for my ivory ball.
Clear 30.6 qt tub, 15 3/4 in x 19 11/16 in x 7 3/4 in. (*Also does it really matter what type of plastic tubs you use for your herps?)
Thanks!
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There is no set answer, depending on your temps, substrate etc it may vary so here is what you should do.

Melt a few holes, setup your tub (heat, substrate, water dish), make sure the temps are stable and optimum, get a humidity reading, melt down a few more holes if needed, get a reading again, melt more holes if needed etc.

Ditto! Start with few holes and add. It is easier to add then to have too many. Size of the tube depends on size of the snake.