This is one of the best tutorials I've seen on starching fabrics. I have used this technique many times and find it really helps in preventing stretching. You do not need to wait for it to dry but running your hands over the fabric after you spray seems to really help keep the flaking down. Give it a try and see if it helps you. I find it very easy and effective. Makes my fabrics look great.
http://www.daystyledesigns.com/starchfabric.htm