33, 2 Kids, 5'3" 125lbs Going Bigger

Hello! Tommorow is the day I go to pick my size. I've very nervous and excited about choosing the right size. Had my first augmentation done 12 years ago, went from a barely 34A to a full 34C. 270cc filled to 300cc, saline. The looked great, but after so many years and nursing 2 kids they have shifted to the side a bit and now I'm only a full 34B. I'm 5'3" 125lbs, "fairly" in shape, size 2-4. I'm worried about going to small or too big. I have basically nothing to start with, PS says I'm about 90% implant now. I like a large natural look, would like to be a full D. Looking at Inspira 450, or 485cc. Maybe Mod. profile or just the regular silcone, not inspira. I have a wide BWD at about 14-14.5 which I think is wide for my size. I want more fullness at the top and to close the large gap up. When I lay down the implants are under my arms and I'm complelty flat. I have great side boob but thats it. I don't want to look fat either. Any advice on size picking a size??

We went over sizes today and we decided on 500cc HP classic Silicone. I was looking at 450 or 485 so I'm panicking at the 500 number but he assured me it will be fine. I tried on sizers for 450 and they didn't look much different than my 300cc I have now. So we tired on 550cc and they were too big, so we are going middle of the road. Because they are to the side he will go in and cauterize the pockets to bring them closer together. Mine are very wide set so my goal is more cleavage and fuller upper pole. I asked about the Inspira but with the look I want which is a large natural look, the inspira maybe too full for that. I'm excited!!