Do you have Maxine Rosenthal's book, One Block Wonders? On page 17 she says that 9 yards is enough for a queen size or larger quilt. This sounds too general to me, since queen size ("or larger") can vary so much. How big does your quilt need to be, and will it all be OBW's (or will there be borders using another fabric)? By 6 wedges per unit, do you mean you will be using hexagons rather than octagons? Smaller hexagons will use up more fabric than larger ones because there will be proportionally more fabric in the seam allowance.
To give an idea - a large queen (102x112) requires 8 yards of fabric just to cover it (with no seams). Add in the seam allowance and the waste in cutting, and I'm not sure 10 yards would be enough for a quilt that size. But you may be going for something much smaller.