Backlight timeout

Hi,

I'm wondering if the battery life would be improved if the "backlight timeout" is set to 15 seconds or 30 seconds, rather than "stays on". This is what I have always used with my 8xx's.

Has anyone tried this yet or have a video of what the display looks like outside once the backlight is off? (Given it is different screen technology than the previous 8xx's.

Thanks