Replacing 300/315cc for 485cc Sientra Silicone Gels After 15 Years | 5'0" - 110lb - San Mateo, CA

I'm 37 years old, mother of 3 children ages 19, 13, and 7. 5'0" at 110lb. I had my original implants done in 2000, after having my first child. They have held up really well - very mobile, soft, no activity restrictions, and with great sensation; but after the 2 subsequent pregnancies, I experienced some involution. Also because my skin is very thin, the rippling in the implants is evident to the touch when I lean all the way forward. The implants I currently have are old McGhan Model 68 Moderate Profile Salines with diameter of 11.9cm / projection of 4.1cm. Incisions were in the axilla areas. For the duration that I've had them, I've been VERY HAPPY WITH THEM.
I do feel, however, that replacement will these implants that have reflux valves will be inevitable at some point. I felt that it would be easier to mitigate with a replacement now, rather than wait for a rupture. I also just wanted to go bigger to stretch out the loosened skin and to switch to silicone - as only salines were available for first time breast augs back when I had my originals done.
SO! My goals for my replacements are: size enhancement - lateral, medial, and in projection, softer feel, improved smoothness, and for longevity - as I hope these will take me through for the long haul. That being said - I don't want to have any on sizing regrets in hindsight. I originally wanted to go for the 450cc range. My (WONDERFUL) PS and I discussed many factors in the sizing process... my desired goals, the tissue loss with the removal of my current implants, and also the fact that well over 50% of women with BAs report that they wish they would have gone bigger and that they liked their breasts most when they were swollen. These things considered - he suggested going up a size to the 470cc - 490cc range. Being that I really love the shape of my current McGhan's I went and looked up the dimensions of that size range in the same model that I have now. Then I found the Sientras that most closely matched up in dimensions and ended up deciding on the Sientra Moderate Plus 485s. They have a diameter of 13.6cm and projection of 4.8. This may sound really big for someone of my stature - but I really think it does depend on what your goals are. The next size down would have been 435cc, and I just don't think a 100cc increase in volume would have been enough of an upgrade for me. Plus, I have the utmost confidence in my PS. He does, after all, have +20 years experience! He also did my tummy tuck in 2006 - which AMAZINGLY survived my last pregnancy and returned to its post-op condition very quickly after my son's birth.

before I say goodbye to my first set of twins!!