[Karren H]

I really think a smaller one will not help at all. When you suck your breast into a small dome it puts everything in compressing.

I've tried tape and making gaskets and they get sucked into the dome when you start pumping.

What I have done I domes too large at the base is modify them. Using heat to reshape the rim. I use the stove (gas) to warm the rim up and the bend it to a shape that will fit better. Don't hear it too hot and let it cool slowly. Do not put it in water to cool it! I've done that. Crack!! If you have a heat gun that works too. Doubt if a hair dryer would get hot enough. If they aren't working then might as well try to make them work.