How tall can a snake stand up?

Interesting.

Is this 1/3 to 1/2 their maximal "stressful" height (like we humans can temporarily stand on our toes to be taller) or is it their normal "comfortable" height? Do the snakes actually like to be standing up usually or is it just for special occasions?

I am wondering this because you have told me an enclosure of 1/6 of a snake's length is good. It sounds like the snake's standing up height is irrelevant to the enclosure dimensions.