After talking with my dad, a former tool and die maker turned supervisor, I told him about a couple of options I saw. I also told him about the size I was aiming for and the amount of exposed floating area.

He constantly said to go with polycarbonate, a material much like lexan AKA bullet proof glass. With 1/4" sheets, he was worried about it bending even over such a small epxosed area and said suck it up and just go with the 3/8". The cost between the two is decent but not the worst.

All the SKU's are from McMaster-Carr

Polycarbonate Sheet 3/8" Thick, 48" X 96" (8574K76), Clear costs $267.51 each. The 1/4" (8574K75) costs $159.45.

To save cost here, i could order 2 48"x48" (8574K65) at a cost of $92.29. This would cost 184.58 per grouping and the added benfit of a thicker material.

There is Abrasion-Resistant Polycarbonate also. The costs for using this material goes up greatly. For a 3/8" Thick, 48" X 96" sheet, it costs 651.64. DAMN ... I'd use the trick of using 2 48"x48" (8707K145) which are 190.07 bringing the cost for this to be $380.14. Still royally expensive but no scratching.

Now this still leaves me with the need for an additional middle layer to diffuse the light. I haven't decided on this middle layer yet. I'm afraid to buy a film that ends up being way too opaque