Need help with custom made setting

[davidmarcs]

I am having a custom made setting made for me, it is based on a ring that I saw that was for a 1 carat diamond. The ring that is being made will have 5 smaller diamonds (7 or 8 points per stone) on either side of the center diamond wich is 2 carats. The dimensions of the center stone is 8.09- 8.11 x 4.99 mm, and will have a 4 prong tiffany style setting. I am not sure of the thickness of the band that I should have them make in order to keep it proportioned to the center stone. I was thinking between 3 and 3.5mm. Does anyone have any suggestions?
Thanks for any advice.