As a wedding/social occasion boutique owner, I can't emphasize more that you need to think ahead for your wedding. Be realistic .. and not be the "Bridezilla" in what you want to wear..mom's too!! Prepare your budget ahead of time, color scheme..some colors are not going to be available..so you will "need to come out of the box" and be flexible.
Many stores are now limiting their Inventory..it's just the way it is right now! The economy has effected all of us. Be prepared to "SPECIAL ORDERED" your wedding dress and Mother of the Bride/Groom dress and pay a deposit at the time of your order. That means each dress you order will require a deposit, even if you want to see how it is going to fit, and the companies will charge a re-stocking fee if the dress is returned. Your store that you are dealing with is not going to "front" the cost. They will give you the best advice they can..you will have to listen and work with them and be considerate of their time!
Be considerate of what they do have in stock when trying on the garments. They are not selling samples but actual inventory. If your size is not available it can take up to 14 weeks for your dress to arrive. It is made for you , so it will be yours to keep.