I also only had to drink barium for the SBFT I had, and only had to do flat x-rays. It wasn't too bad but at least now I know they might add pop rocks and do other "fun" stuff if I have to get one again. I am glad you finally got the more pleasant version of the test :D
I agree that it's important to be your own health advocate because it seems like the nurses and technicians usually aren't paying much attention to your charts. Unfortunately I also have found that by asking questions so you can understand what's going on, like "What's this stuff do that I'm going to be drinking?" or "How does this test work?" or "Will this medicine make me feel funny or sick?" it does make a lot of medical staffers get mad at you and treat you like you are being "difficult". It's so worth it when you get someone who understands you are just trying to get an idea of what's going on, usually those people also enjoy explaining that kind of stuff and you learn all sorts of useful things about how your insides work
I do so hate it though when you are being attended to by people who are seriously lazy or ignorant... I am allergic to acetaminophen (tylenol) and I can always spot the lazy staffer because they're the ones trying to give me tylenol, or drugs that contain tylenol, even though it says on my chart, in the computer, and on my wristband that I'm allergic to it. If they had been doing anything to check for drug interactions, anything at all, they wouldn't be there handing me that cup of tylenol! Funny thing is, about 50% of the time when I tell them I can't eat the stuff because I'm allergic to it, they go "I KNOW THAT" and get all huffy. Oh, so you're trying to kill me on purpose?