I have found growing pot to always be a little more expensive than I want, but it always beats paying street prices. An old wise one told me that. You have a very nice grow spot developed already, a new door installed with circulation fans top and bottom, and exhaust vent for hps cooling tube seems like money well spent. Moving the ballast out is a big plus.
Light baffles are pretty straight forward, light travels in straight lines. Air can turn a corner.
Switching light timing in the middle of a grow does not work for me. Might as well have a timer f#ck up. I do run at night 9-9 because of heat and to balance the usage load. Many power companies have an additional charges for high demand. Watering your patio at night might work well.
Last on the list, switching to a dimmer light at the end of a grow works for me, think in simulates the fall season.

??? If neighbors might see the light, might they also see pot growing on the patio?