Also, were you planning on geting a baby snake or a full grown one? Remember these guys are escape artists, and they will escape when you have an "escape proof" cage. I know those sliding locking tops are great, you just gotta make SURE they are closed ALL THE WAY, EVERY TIME. or else the snake will get out. the driftwood, or anytyhing to climb on for that matter, will be used as leverage to escape.
A note on substrates - the beadabest by itself is enough. if you add wood chips you will need to feed outside of the cage, or the snake may smell the rodent on the chips and eat it, causing extreme vet bills. Dirt ....i just wouldn't use. Peat moss works okay but corns love to defecate a lot, so you'll be cleaning that a lot, and it tends to get to be a pain. I just have astroturf, take it out once a week spray it down with a hose and put the other piece in. Works great.
As far as plants go, I would also reccomend to stay away from live ones...they won't last long with your snake crawling all over them. Get some good fake ones. I learned this the hard way.
Housing together - Corns are not cannibalistic. They can live together, however don't expect to seeing them curl up together. Right now I have my two baby bairds living together, but thats out of not having enough money to buy a whole other tank setup...and plus with me building my large setup now it's a waste of money. The only things you really need to consider when housing together are the following.... you will have to feed them both outside of the tank, as to prevent fighting over food. I've known some snakes never to eat while I watch before. Some snatch it out of my hand. Also you have the concern about health. If one gets sick, the other will too. Double vet bills.
Additional note - I (as well as most responsible snake owners) urge you to feed pre-killed mice. Rather this be buying frozen mice or raising them and killing them yourself, by the time the snakes need a large mouse to feed on, they can be seriously hurt by the mouse, even to the point of death. Talk about your irony, right? Mice and rats have claws, and they know how to use them (just like my girlfriend lol). I couldn't handle killing animals to feed to my snake, so I just order a bunch from rodent pro..however their minimum order is 100...you may just prefer to buy from your local pet shop.
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The reason mainstream thought is thought of as a stream is because it's so shallow. -Unknown