I came home after 5pm, headed for the back yard and within minutes a female showed up and hung around until after sunset. It looks like the same bird that stayed around all last summer, and unlike the males that have been coming so far this year, she didn't seem to mind when I moved my chair quite close to the feeder! I'm usually up very early and I fully expect her to show up before sunrise tomorrow (I'll be ready with my camera(s) if she does).
As for nectar, I always mix my own and would never consider using the store bought stuff. I also replace the nectar and clean the feeder at least once a week and sometimes more often in really hot weather.