We use a MDF Lite for making molds for vacuum formed faces. All I can say is keep it climate controlled, it seems moisture is the biggy. We keep ours outside under an awning, because warpage isn't as big of a deal for what we use it for. When stacking sheets (we use 60"x97" 1/2" and 3/4") keep them stacked tight and if you have them up on driers (lift boards for the forklift to get under), use no less than 4 pieces that run full width of the material, and of equal heights. When cutting on the router I put the crown of the material to the table, turn on the vacuum. usually after cutting the drop will bow but the usable cut area for us is fairly flat.
Hope this helps!