@Aus, It's not only the memory card you should consider but the number of shots the battery will shoot at a quality you want, if you can charge up every night it's not a problem. Personally I shoot at the highest jpeg image the camera will produce.
Cards are cheap so I would shoot as much as possible and see what results you get under different conditions, don't forget camera's are so good now, using auto and program modes still takes good shots. Better to use these modes than miss an opportunity, looking at the exif's later on will give you an idea of base setting for future use if you use App mode. Have fun.