First, a general comment about your choices. They are so close together in volume and dimensions that I doubt it will make a great deal of difference. I remember a study done several years ago where they had independent evaluators look at round versus oval implants. The oval implants are narrower, but taller, with better projection. To the investigators surprise, as well as mine (I was a big fan of oval implants), neutral observers couldn't tell wether the implants were round or oval. So much for fine tuning the appearance of implants!
Whether these implants are large or not for you, don't let anybody override your instincts. Ultimately, you have to be happy with them. The biggest source of implant dissatisfaction are size issues, and patients usually wish they had gone larger!
As far as your frame, a moderate profile implant will look more "spread out" like a normal breast, whereas a high profile implant will be more perky. With your body frame and weight your implants will look like implants, because there is not a lot of tissue surrounding and disguising the shape of the implant. I have done a lot of patients like you and they love the look. I have to say it is not my taste, but then again I am not the one wearing them.
Since you are going big, I suggest you consider other factors such as positioning, which ultimately have a lot to do with appearance of the implant. Check the blog post below to see a comparison of different implant positionings.