Gutter pitch (drain, install, standard, vent)

[j groth]

What do you think is an appropriate gutter pitch for about 24' length?
Google opinions seem to vary.

[T. Damon]

Actually it is assumed that you can install a gutter perfectly level. The drain hole will always be lower than any water level.

[texdav]

The standard is 1/4 inch for every ten feet. That is upto as I reacll 32 feet. Over than the high point is at the center to prevent overun with down sp[out at both ends.