Before I figured out the size of my cuts, I selected an empty container to use. A big one is preferable (large protein powerder containers work really well). The drawn diagram is one side of the wood that holds the container. It will be slightly shorter than the entire length of the container, i.e. as you can see from the drawing, the length of wood from the too lowest dowels to the dowels at the top is the length of the container from the very bottom to the top just under the cap when twisted on.
To create this I used only 1 by 2 inch pine scraps, and various sized dowels. The top (smaller) piece of wood is as wide as the top of the container if the dowels are slightly wedged under the container lip once the cap it on. The lower piece of wood in the drawing is longer because it wedges the container in at the widest length of the container.