Fett armor is best done with sintra. The jetpack and gauntlets really benefit from the more rigid sintra. My first set was made that way. Lots of good templates and advice over at thedentedhelmet.com. Check them out!
A sharp hobby knife and a heat gun can do really impressive things to sintra.
You can do great things with sintra if you're patient. One thing you'll want to do with your Fett armor that a lot of people overlook is adding some depth/thickness to it. You can just cut it out to shape and heat it to shape it, but it'll still just look like a thin piece of armor.. double it up and bondo the edges to make it look like real armor.