Enclosure size for large colubrids?

[SeaStorm]

I'm interested in keeping some large colubrids in a year or two so I want to make sure I'm prepared. Right now, I'm trying to figure out enclosure sizes. I'm particulary interested in Beauty, King Rat, Tiger, etc. snakes and I do know they get quite big.

Would an enclosure that is 48L X 23W X 14H be good for a large colubrid? I was actually thinking about buying an enclosure this size and then sectioning it off and give them more and more space as they grow.

Also, I've heard of some people keeping pairs together as they grow, is this recommended at all for any of the large colubrids?

Thanks!