Thanks, guys. And yes, Jon, that is the bridge that I am trying to pattern mine after.
Mark - I am using 1/4" thick flexible foam that is used for insulation under metal siding. It can be worked just like any Styrofoam, but is thin and will flex or bend to the contours of my framework.
It has been a little frustrating at times getting to this point, but I hope that I am finally on the right track.
Art