Barry, as I said in the linked thread all you can do is try it and if you feel adventurous try other ideas as well and 3mm MDF is a cheap way to prototype designs if you want to try different ideas. I wouldn't think the sloping curved top is necessary but then I haven't got a clue and it may work better than a flat top. if it were me I would build the thing in 3mm MDF if only for the patterns.