So i need to do an 8ft x 12 ft portrait. Which I would like to create as a seamless piece. Normally when I work in this scale I only need to use plywood painted and sanded after attaching to 2x4's. This piece however will likely need a bit more assurance that the seams will not split and need retouched upon flexing and likely need to be thinner than being backed by 2x4's. It will be indoors. My Idea Is to double up on 2x2's and use fiberglass over hardboard then use duratec (a high build primer) to build and sand out a smooth surface. I would like to hear some other Ideas though if anyone has some.