Great article. It inspired me to do my own wetpallet. Due to difficulties getting the right materials mine is buildt out of a wettex-rag and some sandwich-paper. Total cost something like $2. It works perfectly though
I have tried a wet palette as well in the same size you have using a collectible card game case (with a nice tight lid). It certainly keeps the paint wet even for days. My only problem is I find that the card size of the palette is not big enough to have several different mixtures at once. I tried seven once for layering and the paint was starting to mix with each other. I like it a lot. I suppose a bigger palette is all I need (maybe using one of those ziplock containers).