Sounds like it was pushing it, eh? Maybe for the better then that she didn't keep it down. I hear ya' on the petshop thing. Seems like every time I go looking for a particular sized rat or mouse, they have everything but what I want. That's one reason why I breed my own now. Other main reason would be that I don't much trust petshop feeders, or their source. Too many unknowns and potential problems.
I've read somewhat conflicting ideas about the girth thing. Some say about the same size as the thickest part of each (which would be in the neighborhood of your %110 Fangs), and then others say only enough to cause slight bulge once swallowed. There are certainly a few schools of thought on feeding. Some say one big item, while others say multiple smaller items. I don't really know that there is a right or wrong, or any one definitive answer.
I personally lean toward one prey item about 20% by weight, which usually works out pretty close to the same size, or slightly larger, by girth. Seems when I feed what seems a reasonable size, none of my snakes want a second item when offered.
