As you can see the can on the left has a rounded wide bottom ring and the one on the right is narrower and more vertical. Using different type cans bottoms, even though they are the same brand (Pepsi) will cause possible problems when using an open top stove design. This is because the inner tube will not fit vertically if the diameters of the rings are different. Both styles will work if the same type can is used for the top and bottom. I personally like the narrow more vertical type as it gives a bit tighter fit when assembled. I suggest using tape to test fit & find the correct diameter prior to applying JD-Weld and not just using the dimensions provided in the construction web sites. This way you will have a proper tight fit.