RE: glass shell??
I have seen on a auto show on tv that they used floral foam to make a mold then covered it in alum foil and layed the glass on top of that and it relest . hope there wasnt any movie magic
im building one now and im useing some 3" blue board foam like you get at lowes but im leaveing the foam under the glass i figer itr should float better and be hold up from hitting things