My son had issues early on and was supplemented with bottles. Then he refused to breastfeed so after 6 weeks of pumping and trying to get him to latch and refuse, we switched him to full-time bottle feeding. I tried the First Years bottles at first but he had a problem getting a good seal when sucking them and we switched to the Avent bottles which I had used with the my daughter and to supplement my first son.
We don't have a problem with the size 1 and 2 nipples but for some reason the size 3 nipples allow too much liquid to come out to quickly. My son is now 10 months old and still uses the size 1 and 2 nipples. We have a few size 3 nipples but only use them for juice because of how quickly the fluid comes out. I think it is less a problem with the seal they get more a problem with how quickly the fluid comes out. At the same time, my son doesn't have a problem with sippy cups or straws. I think part of it is expectation on their part, what they are used to and the position they are in when they are drinking from each. He is more upright with a sippy cup or a straw.
At any rate, my advice is to switch back to the size 1 or 2 nipples if she does okay with those. They may match up more closely with the pace she gets her breast milk when she is breastfeeding.
I have to say, I didn't have this problem with my first two kids. Just this one. So maybe they have changed something with their nipples in the past 3 years as well.
I've also experienced the leaking problem that others have spoken of. Sometimes it can be frustrating. It seems to be caused by a couple of factors. If the silicon doesn't line up with the bottle when you screw it on or you don't screw it on tight enough it can happen. But it tends to happen more with nipples you have had for several months as opposed to new nipples. So it could be an issue with degrading of the silicon after months of use and washing or with soap/water residue (in the case of hard water) left on the nipples. Anyhow, I don't think that is the real issue you asked about. And since you seemed to have success with the size 1 and 2 nipples, I suggest switching back down to them.
Anyhow, good luck. I hope this helps.