I've found that the 10cm size, which I think I figured out was roughly about 2 1/2 cups, was fine for the dinners and other meals I needed to cook in it. Obviously it was just for me, but I was able to put some good volume meals into it. I use it with both my cartridge stove, and my alky stove, and it really is a solid and way cheap set up. Weight wise it stacks up against the TI options for a fraction of the cost. The cozy that I built for it is critical, and I've had food still too hot to eat after 10 minutes of cozy time. I left the handle on mine, and built the cozy to fit around it. I just use a bandana as a pot holder, and I cut and flattened a small piece of aluminum to work as a lid. I might have to invest in one of the Minibull lids, they look well made.
I finally had success at another Wally world location, so I bought three of the cups to make sure I had some for the future!