Hi L,The difference you are concerned about is just under a shot-glass. However, most women, in my practice, wish they were bigger a year later. So, keep that in mind when you are on the fence. I would recommend you also revisit the PS's office, and have the staff help you with our final decision. You are not alone, as this is a tough decision, and many, many patients agonize over small size differences. I already know you are in the good hands of a board certified plastic surgeon, because Sientra limits their product to BC PS, exclusively.Since you have two weeks to go, here are some tips and tricks we use to help our patients out. Cup size estimates can be misleading, but I generally advise patients that they will experience an increase of approximately one cup size per 200 cc. You can try on implants in the office by placing them into a special bra.Approximately 50 cc (1-2 oz.) is added to the final volume to account for flattening of the implant in the partial submuscular pocket. Once you decide on a size you like, then add on about 25-50 cc, because in real life the implant will be flattened slightly by your tissues.Multiple measurements need to be taken to fit an implant to your exact anatomy. Have your surgeon's office show you the charts of the implant dimensions for the various profiles of silicone and saline from the manufacturer. Then you and your surgeon can piece together the puzzle by matching your measurements, with your wishes, versus your tissue cover and the available implants to arrive at a surgical plan.Keep in mind larger implants tend to have more problems over the years.Since silicone implants wrinkle less than saline implants, they might be your best bet.You can also approximate this at home by measuring out an equivalent amount of rice placed into a cutoff foot of old panty-hose, and put this in your bra.Wear this around the house for a while, and see what you think.Implant size must square with assessments of tissue cover, breast diameter, and chest wall width. Multiple measurements of your chest wall are taken (seven in total). Implant size selection has been an issue of much discussion. Therefore, I use a wide variety of methods, but the implant size is always established preoperatively.Also, patients are advised to bring reference photos demonstrating their ideal size and shape. A photo album of patient pictures is maintained to assist them. These photos ultimately help in determining where the implants will be placed, since they can be shifted inside (to provide more cleavage), to the outside, up or superiorly, and down or inferiorly during surgery. In determining the final size selection, I always place the highest priority on the preoperative measurements and potential tissue cover. Then, the patient’s verbal requests are factored into the analysis.Be sure to see only a board certified plastic surgeon (by ABPS - The American Board of Plastic Surgery) who is a member of ASAPS (The American Society for Aesthetic Plastic Surgery) and or a member of ASPS (The American Society of Plastic Surgeons). I wish you all the very best for your upcoming surgery, “Dr. Joe”