Roof Insulation for Victoria/Closed Car - Suggestions?

[tquigley]

Seeking suggestions for material to use in the roof of the Victoria. I have insulated and sound deadened the entire body, but need to install some means of insulation or sound-deadener under the overhead fabric headliner. Bubble pack is unsatisfactory because it makes noise while traveling down the road. The top material moves enough to create that "crinkling" sound. The boss hates it. Suggestions?