If you really insist on having a white interior (or off white, painted panels), we can supply 3/4" plywood triangles. We use a special premium grade of plywood with the surface being sanded. You can then finish them while they are on the floor. The batten strips at the edges of the panels can be painted or stained a contrasting color or they can be finished in the same color. Prices vary with size of dome - let us give you a quote.