Found this resource here:
http://www.rplastics.com/plasticsheet.html

ABS Textured Plastic Sheet 0.125 24" x 48" $13.36
PVC Gray Type 1 Sheet 0.125 24" x 48" $19.68
Clear Plexiglas® Acrylic 0.118 24x48 Sheet $25.28

There is one 40" x 40" window which I would like to preserve
for natural light and observation of the storm, thus I need
a Tufftak/Lexan type material.

I have E-mailed them to as if their .236" Tufftak (Lexan like)
sheets are adequate to the task. WDYT?

I wonder what the non-discolor life expectancy of the panels
is on a north facing window in west central Florida just north
of Tampa?

Would a plastic sheeting, e.g. 'hurricane film' used on glass
windows, applied to the Tufftak, lengthen it's life exposed to
the weather?

Finally, the 'sandwich shutters' will depend on the strength
of the steel folded over at the ends where the hinges will be
attached. How would one attach hinges and latches to Tufftak
and not violate its integrity? Are stainless steel piano
hinges preferred to three-hole door-type brass hinges?

doc