Where/how many holes on an iris tub?

So I find that not getting much sleep then 6 hours in a car is bad for judgement, hope not too bad tho.

Picked up my new RBI sweaterbox rack today, and when I went to put holes in the tubs I put 2 rows of 11 holes, along the bottom of the front of each tub. (front face right at eye level for a lying snake.)

Of course if I was thinking straight, I would have asked FIRST how many holes do people find they need on their iris tubs and are the holes being along the bottom of the front (about 1/2 inch from bottom is shallowest where I missed my aim with the sodering iron) a bad idea?

I think my logic was that CO2 was heavier than O2 and I wanted it to sink out, while the heat would rise and I wanted that to stay in.

So how many holes and is putting them along bottom bad (I use paper for substrate so they won't get covered at least).

Thanks, a little foresight woulda made this a bit easier.. haha.

As far as the O2/CO2 argument - Interesting, but I put my holes at the top and middle of my tubs and have not had any problems with sick animals. However I am also very careful about cleanliness in my snake tubs, and my tubs get opened often enough to allow my snakes some fresh air, so I'm not too worried about it.

Holes at the bottom would make me nervous that certain ophidian bodily fluids would make their way out of the tubs... ahem... my adult bp's urinate A LOT. And sometimes they splash their water bowls. I'd at least put some extra paper down towards the front of the tank, or something absorbent to avoid that happening.

What I would do if you are trying to control humidity: Put in one row of holes and then test your humidity. If it's too high still, put another row (or half a row) and keep doing that until your humidity is correct. That's my 0.02.

5 on each side of the handle on the front and same in the back