@woodsrunner thank you for the encouraging words!
I was quoted about $10,000 to replace all 7 of my windows, or $3,000 to replace just the 2 back windows (I do live in the rip-off capital of the world), and I decided to go with lower-tech methods.
I have heard other people recommending taping bubble wrap over windows. I should pick up a few rolls and keep them for a third layer.