Concerning the black water cans: You will have difficulties finding pictures of small black water cans. I wanted to place one on one of my models and my israeli friends said, they donīt recall having seen a small size one during all of their army time.
They are indeed not plentiful on the net. It would seem they were used primarily on the M151. They appear in print media as well, to wit: Zaloga's Tank Battles of the Mid-East Wars, 1948-1973, page 68.
To avoid confusion, the above photo is not from the book, but rather the net.
Steve, in response to your last question: The WATER cans are black, unless using the US ones I mentioned. The metal fuel cans are generally the same color as the vehicles, although other colors were used. If you go with the German pattern you will not be wrong.