"Im buying some ND filters to take with me as a backup just in case"

I'm not sure that these will help you any. They reduce the exposure over the whole scene, so all you end up with is an exposure taken with a wider aperture, slower shutter speed, or higher ISO. The scene will look the same, exposure wise. ND filters are most often used with brightly lit scenes where you want to use a slow shutter speed to obtain motion effects, like flowing water.

Alan