6 mm oil tempered hardboard has worked on Florin for the last 10 years, & still O.K. The slight flexibility allows the board to pull down a little onto the top/side chassis rails, & the base line is re-enforced with 38 mm radius softwood; which then holds the base of the glove box.
Glove box ----- our is probably larger than some boots --- the smallish door surround holds the edge of an industrial hoover bag, which allows Kit to fit in right up to the fire-wall/wiper motor/ instruments/scuttle.