I agree try the size 2 and see if it helps. It may make her spit more or even sputter (per lack of a better turm..) for the first few feeds, but she will get the milk more easily. If the spitting does get worse however, I would say go back.
Another option is to try the try flow, as you can control how fast the flow is depending on the feed. I found with DD some feeds she needed a faster flow then others, like evening and morning feeds, and it was a pain to keep switching nipples.