Huh, that seems like nearly the cheapest way, and certainly the best value. Even if each window uses an entire tube of sealant, and I need to buy a new caulk gun, that would be $216 for max visibility.
I wasn't aware it's that straightforward to install glued-in window glass yourself, or that it could be had that cheaply. I'd also seen people say that companies don't want to ship bare glass. But, in my experience Amazon doesn't think anything of just giving your money back if something happens to the package, so no worries there.
Unless the complete doors come up, or anyone has any other ideas, I'll probably go that route then. I'll throw up some pictures as well, but things are hectic and it might be a few weeks before I have time for the project.
Thanks!