If you are storing up your energy for night usage this is probably best. Regular daily weather patterns may effect you choice of angle, so, for example, if you mainly get clear mornings and clouds build in the afternoon, then consider angling them a little to the east to catch more of the morning Sun.
Dan, it looks like the larger tank is inside your structure. Is that the 500 liter tank? That sounds small for the amount of rain you will get. Can you fit a 1,000 liter tank?