T.W.
I am an A cup too and on my 4th baby. I have had 3 different breast pumps and although some of them extracted more milk at a time than others, I did not see a difference in any of them due to my size. I did however like the softer cup rather than the hard cup (just personal preference) but it still did not make a difference with the actual pumping. They all fit just fine and pumped just fine.
Good luck!