Style 8567 Apple Red Size 6

Hello, I was interested in perhaps purchasing one of the Style 8567 apple red bridesmaid dresses from David`s bridal that you have listed on your site. I would love to know what the measurements for the size 6 bridesmaid dress are. I may need a size 4 for this particular dress. Do you know if I could find a size chart for David`s bridal bridesmaid dresses? (I checked their website, but couldn`t find one). What are your return policies for your dresses if the size is not right? Thanks for replying!