question about air

so i am getting ready to swap my girls over to 41 quarts, the gap between top of the tubs and the bottom of the next shelf is 1/8th of an inch roughly, how many air holes do i need and what diameter would be good to give them nice fresh air flow?

From all I have been able to find, the number of air holes is more dependant upon the humidity levels. That 1/8" gap will get the fresh air the snake needs. I'd put a few 1/8" - 1/4" holes in each side of the tub and then let it sit for a while with water bowls and heat on. Check your humidity. If it's too high, cut a few more holes. If you find the humidity gets too low, put tape over a few holes.