There used to be a product called an "Easy Curtain" that was blackout nylon. It had 2 pockets that fit over the sun visors to support it over the windshield; then it wrapped around to the driver and passenger windows - those parts were held in place by closing a flap of fabric into the top of the window. The company is out of business, or at least they were when I was hoping to find one to fit a transit cab.
Re my Transit: I ended up using a jumbo sun shade in the windshield; and cutting Reflectix insulation to fit the side windows - I added some magnets to those (just taped them on) to hold them in place and they worked great. That would certainly work for the E-series, too
Ed, Deb, and 2 dogs
Looking for a small Class C!