If you are going to make tulle pew bows, buy tulle by the roll - not by the bolt. It comes in 6" wide and usually has 100 yards or more on the spool.
Trying to save money by cutting the 45" or 54" wide tulle to make bows will just give you a lot of headaches - it's not worth it! How many spools of tulle you will need depends on the size of your bows.
Here is a simple chart:
∙ 8" diameter Bow - 3 yards for the bow and 1/2 yard for the tail
∙ 12" diameter Bow - 4 yards for the bow and 1/2 yard for the tails
∙ 16" diameter bow - 5 1/2 yards for the bow and 1/2 yard for the tails
That means that out of a 65 yard bolt of tulle you can get approximately 18 small bows , about 14 medium size bows, and 10 large bows.
On a cardboard backing, mark the diameter of the bow you want. For instance, if you want your bows to be 12" across, then measure that width and mark it on a piece of cardboard.
Tulle can be very slippery to work with. You need to fold your tulle back and forth like an accordian pleat. Pin the cut end on the first mark with two corsage pins. Fold tulle back to second mark. Pin with two pins.
Continue weaving back and forth, removing each pin separately, repinning each time to help keep the layers of tulle in place.
Keep adding more layers until you have the number of loops you want on each side. I usually do at least five on each side to get a good full bow. Pin all four corners securely.
Take a 3' length of tulle and slide one end of it with your hand under the pinned layers. This length of tulle is what you will use to tie the center of the bow.
Pull both ends upward, right in the center of the layers of tulle.
Make a square knot with the cut tulle in the center.
If you want different colored tails, or more white tails, add more lengths of tulle in the center, tying each new tail into a square knot.
Upin and put your hand inside each loop, pulling the out of the layers. Give each loop a sharp twist.
Continue until all loops on both sides had been twisted and fluffed out.
Tie over a hanger and hang on curtain rod. Do NOT store in bags or bows, as this can crease and flatten bows. Wait until the bow is fastened to the pew to cut the bottom sashes to length.