You should defiantly get a dome that is wider than your breast.... if you measure your breast you can go look at the data in the Dome Size Database thread and see what would work best... I think pumping fills your breasts out and helps long term growth.... did for me so far..
www.breastnexus.com/showthread.php?tid=19940
www.breastnexus.com/showthread.php?tid=19940