HI there, when I make my ruffles following the Maggie Austin technique (she uses a pasta machine and I don’t have one yet), I hold the piece of fondant in my left hand and with my right hand, I use the roller to stretch the fondant in one direction only, going away from you (no back and forth movement). I hope I am explaining this right. It really thins it out. However, I am doing this on small stretched of fondant, yours is much bigger but you can still try :-)
Love your cakes by the way :-))
Dina @ miettes, http://www.facebook.com/pages/miettes/257790597632317