I think that, if your medical team has not given you any definite guidance on which option, you have to think about what you can live with as no-one else can do that for you. The recommendation these days to doctors seems to be to go in with the least intrusion possible but it should also take in your preferences as only you know what you can manage (which seems to be what your doctor is offering). I'm sure that if you choose the minimum, if there is any doubt about margins, you will later be advised to have a mastectomy. My suggestion would be to write down your pros and cons for each procedure.
For me, I started with a lumpectomy, only to go back in a couple of weeks later for a mastectomy due to the margins. At the time, my surgeon said that we should only be considering removing the affected breast. Twelve months later he said that if the scanxiety got too overwhelming for me then we should consider removing the other one.