While most people use kransekake molds which set your cake to be a certain size, you can still make a beautiful cake without them (the molds, not the people).
Either way, always start by rolling out the smallest rings and go larger. This makes sure they will stack and it also makes sure you don’t come up short before you get to the smallest ring, leaving a huge opening in the top of your cake.
Here’s what I worked out: make 2 of each length: 4″, 6″, 8″, 10″, 12,” 14″ (they should all be equal thickness – about 1/2 inch around). Use a ruler, it really helps. And work with lightly floured hands. Even with two of the same size, they bake up with slight variations, making a smooth stack. If you really want, you can make 1 each of 4″, 5″, 6″, etc but you might have to think a little harder when organizing them on the baking sheet.While you work, keep the dough covered with saran so that it does not dry out.You can place the rings inside each other for baking as long as they do not touch. I managed to fit them all on two baking sheets.