I did not have a trial..I am a hair stylist so I talked with Ana from Beaute Speciale prior to the wedding to kind of give her an idea of what I wanted and emailed her a picture of my hair so she knew what she would be working with.
I think you will be fine without a trial if there is no way you can have one. Just be clear with you stylist about what you want and bring pictures for inspiration. If you do not like the way your hair is looking while your stylist does your hair please tell her so she can fix it then..if you wait till the end then she will have to start all over again and take more time. We don't get annoyed when you have us fix the problem then and there so don't feel annoying or bad..it is your wedding day and we want the bride to look perfect.
Next month is too early to have a trial..you could change your mind,your hair could be different by 2010,you never know.