My wedding coordinator told me that sheers for the gazebo have to be 12 mts long x 1.5 mts wide.
It was hard to find organza of my wedding colors. So I used http://www.tulleshop.com/Wholesale-Apple-Green-Organza-Fabric-p/310009.htm
Colors of the sheers that i received were slightly different from the colors on these pictures( green-darker, yellow - much lighter), but they were still very nice.
Also I've found on ebay a very nice seller dreampartycreation
I ordered chair bows from them( very nice quality, love them); they also have a nice selection of organza bolts. However, their bolts are 50" wide(((
Hope this helps)