How can you minimize the risk of symmastia? (photos)

I just recently upgraded from saline to silicone (now 550 cc's HP round under the muscle). I'm still recovering, but so far my cleavage has gone from a 3-4 finger gap to about a 1 finger gap, and I'm thrilled! My question is, is there anything I could/should do to avoid getting symmastia? I trust that my PS was careful not to get too close in the middle, I'm just wondering if there is any way I could cause it by moving around to much, sleeping a certain way, or something like that. Thank you for your input.