While I had the bumper off, I decided to work on my solar fan.
Here's the last pic I posted of it:
With the bumper removed I was able to see that the fan wasn't able to push open the rubber exhaust flaps. I taped up all of the holes where air could have escaped, but the pressure still wasn't enough, so I cut up a large sponge I had laying around and fit it to cover the airspaces around the fan.
The fan still wasn't able to push open the flaps, though when I lifted one there was a pretty fair amount of air moving through it. So, I removed one of the flaps.
Not certain if I want to keep it this way. If the car is closed up and has "recirculate" selected when it was shut off, it should be relatively airtight. Leaving the vent open will allow a small amount of outside air and moisture to get in, though less than parking it without recirculate selected, which is usually how I park it.
Here are the panels:
The smaller one has around 6x the output needed to spin the fan up in perfect conditions, and the large one nearly 20x, but behind the tinted glass in the hatch I need direct sunlight on at least one to spin it, and there are plenty of shadows. Chances are I'll leave the panels mostly unplugged until the weather starts warming up again, and then find the best two spots in the car for the panels and mount them permanently. I have a feeling I'll be placing the smaller panel on one of the rear quarter lights and the bigger one centered on the carpet in the hatch.