To get the more textured look on the top tier, I found that if you cover the entire tier, then go back and add more flowers over the spaces where the icing is still showing, you'll get a fuller look. If you have a lot of icing showing in the spaces between the flowers it won't look as fluffy, if that makes sense.
To make the right number of flowers I cut out strips of waxed paper the height and circumference of each cake tier so that I could make sure to make enough flowers to cover those. Even doing that it still ended up being not quite enough, so I ended up making about 200 more. If you make more than you think you need you'll probably have just enough!
Kara Buntin owns A Cake To Remember LLC, online cake supplies at www.acaketoremember.com and www.acaketoremember.etsy.com