Troels, after all, I might turn it at right angle and try my new Old Holland paints on it. But I think I won't.

Andy, a ratio has no unit. So you didn't have to mention the measures are in cubic inches. Nevertheless the question interested me (in a general way, mathematicians are often interested by uninteresting questions to which they can bring a clear and complete answer). Considering the piece of MDF is 1 x 32 x 60 (in cm, this horrible metric unit) while the other piece of wood is 1.8 x 40 x 87.5 (again in cm), the ratio appears to be equal to 3.28125. By the way, that number is not so far from some old approximations of pi, which suggests that this project should turn quite well. The interesting point, though, is that if I had dared show you the second piece of MDF which has the same dimensions, the volume of the MDF would have been doubled and hence the ratio would have been divided by 2, becoming 1.640 625, reasonbably close to 1.618 033 which is the golden ratio, often used to define ideal proportions in painting or architecture. So you see, Andy, your question uncovered some great foreshadow for the future of this project...

Oh Frédéric, I fell asleep in the middle of your dissertation ;-) I love that you call it a clear answer ;o) And don't forget a layer of gesso if you should decide to paint it for a background ;-)