DD is a big implant, even if you are small framed. Some ladies opt for a smaller implant then get the other breast reduced. That means more surgery. It's probably worth getting your surgeon to run through all the possible options with you--which isn't likely to make the decision making process easier, sorry.
I can totally understand your concerns regarding the lumpectomy, sometimes we do need to listen to our 'inner voice' particularly if you suspect it is going to yap on for years about something that worries you.
I had implant reconstructions and now regret that move because my body doesn't like the intrusion and constantly encapsulates them. This is not a common reaction and the majority of women have no problems.