I don't think they skimped on the dry ice. Usually there's a good size chunk (it's fun to play with!).
When I first got my snakes, I looked into all of the major rodent suppliers and remember finding that Layne Labs was cheapest overall - maybe just for the quantities I order, though?
I decided to just feed one of my snakes tonight, Orville, since he seemed the most ready to move onto hoppers. Hopefully he won't regurge or have any negative reactions. He sure took it willingly enough.
I'd actually be more concerned about the pinkies being spoiled because they're smaller (and hence thaw out faster) and I also ordered a smaller quantity of them, so that would also make them thaw out faster. Neither of the pinky-eating snakes need to eat tonight, so I'll have a few days to think it over and decide whether I want to risk it for them.
Thanks for everyone's input!