Your questions about breast shape are common for all women. We all start out with pointy breasts as the glandular tissue starts under the nipple and grows outward from there. After about 3 to 5 years of hormone therapy, the glandular tissue has grown as much as it will.
Now that the breast has grown, gravity take over and this is where any roundness develops. Also droopiness and other not so flattering shapes appear. Add to this weight gain, which some of us are afflicted with, will also change the shape and size of your breasts.
Weight gain also increases the chest size as subcuteanous fat is distributed all over the upper chest. Your ribcage bones do not change in size, so that the only way to get a smaller upperchest is to lose weight. This will also reduce the subcuteanous fat over your breasts, so there is no way to have everything you desired short of a breast augmentation.
Having said that, your results may be completely different and diet and exercise may get you where you want to be. If it does, then good for you. If not, then a good plastic surgeon can help. I was on HRT for 6 years before my BA. I was really reluctant to get a BA, but a good long look in my mirror told me what I wanted to know. I needed more breast size.

I did my homework carefully and I finally found a surgeon whose work I can appreciate. About one year ago, I had a pair of 800 cc silicone implants placed under my pectoralis muscle via a transaxilary incision. I am expremely pleased with my appearance and so do many of the men who casually notice me in my day to day activities.
