Great tutorial for how to make tissue paper pom poms also includes a Tissue Paper Pom Pom Size Chart. It tells you how many sheets to use for each size pom pom as well as what size the tissue paper sheets should be.
Tissue Paper Flowers: Use around 8 sheets of tissue paper for each flower and punched all 8 layers at once. Staple together your stack of flowers . Scrunch up your first flower layer to the center. Repeat with each layer and then fluff back rest