lol man your making way to much of this....either way dim or bright its gonna last a very long time, especially if you only use it for the defaults ( blinks when goes on and briefly for an update)
Im no electrician but i think the strength of the light depends on how many ohms the resistor is allowing to pass through. Thus theoretically the dim light will last longer because there is less heat but led's function with practically no heat that the life span of a dim setting and bright setting would be practically equal
just set it to bright and enjoy your wii