Please consider. The poster asked for a perfect setup. I know, they all do, but perfect at least means good or better.
So you recomend half the lenght of the snake. So a three foot snake can "Stretch" out HALF its total lenght. Does that mean an 18 inch long cage. Hmmmmmmm I hope I am wrong here, but that sounds like torture, not perfect or even good.
I do not have to be a snake person or even an animal person to know this HAS TO BE WRONG. A cage thats half a snakes lenght cannot be called anything but poor.
Of course you could get it to live in a cage that small(at least have a heartbeat) But you could not call it a life, just alive.
And please do not yell at me. Just consider what YOU are saying. Cheers