Wedding dress assessment

My wedding dress came with what seemed like lightening speed. What's weird is that local bridal stores claimed it takes 4 months or more for my dress to come in. This place shipped it within 5 days. They were extremely helpful. I sent them my measurements, which happened to span three different sizes, and they recommended the middle of the sizes. The dress is beautiful.
Barbie came over and helped me try it on. Because the top is a corset, you can adjust it to fit just perfectly. When I tried it on, Barbie laced it up and pulled it tight and it looked beautiful. However, if I lost even a few lbs. it would be too big. And given that I'll be running a marathon a few months before, I suspect I might drop a few lbs.

I took the dress to a seamstress to get her assessment. She recommended a smaller size. So I shipped it back yesterday in exchange for a smaller size. The seamstress I went to came highly recommended from several people on some austin wedding web site, however, she is pretty pricy. Wanted $250 to do the hem. Granted it's 4 layers of fabric, two of which are chiffon, but that seems a little high. When my new dress comes in, I will take it to another seamstress and see if they can give me a lower price. It's been my experience that you get what you pay for, and I'm really not looking for perfection since I'll be dragging the thing across nasty floors and sandy beaches anyway.