n2dvn

This is my opinion only, but I think the main factor in how well skin snaps back is mostly luck. A few other factors may play a part too. However, I'll tell you what I did. I'm 5'7, I've lost over 160 Lbs at this point, going on 170 and my skin has shaped up quite nicely considering how large I was. The largest size I've ever worn was a tight 28W and 3-4X tops. The smallest Sizes I can wear now is XS and 0. Vanity sizing plays a lot into that but I digress...
I drink a whole lot of Water, I tone up when working out and I eat as healthy as I can. I also take Vitamin E 1,000 Mg 4x per week before bed (was every night). I do believe these have helped me a lot in my skin recovery. One last thing, it can take up to 2 years before you see full results of how well your skin will retract. So, patience plays its role in this too. It is also my belief that ethnicity, age and whether you're a smoker or not has some say too.
Good luck to you! One last thing... Plastic Surgery and compression garments has helped!