For the sake of completeness, the Android screen dimming issue can be solved using a deeply buried Dolphin setting.
Settings, advanced, more, Keep screen on.
(dont you just love android menus, yuk)
So to recap:
- Developer options, stay awake ( keeps the screen from turning off while plugged in).
- settings, advanced, more, Keep screen on. (stops screen from dimming)
- reduce screen brightness (or turn screen off) at 9pm
- increase screen brightness at 7am.
Power consumption seems to follow no discernable pattern from any of the above. Dimmed does seem to result in the lowest consumption, although i also saw it pretty low using one of the screen brightness apps.