Hi magic randy. Unless you plan to watch the videos on a TV, there is no real advantage (and the disadvantage of larger file sizes) to choosing one that is larger than the native resolution of the screen on the mobile device. Not sure, but I doubt the iTouch has a screen that large. Check the specs, use the native size. I do all mine at 480x270, which is the native resolution of the Archos 504 and they look great.