Cardboard progress

I've pretty much been spending countless hours rolling cardboard in an angled fashion and gluing them together.  Only near the top have I had much of a problem with the form, as it is now much harder to keep them glued together, and in the proper shape.  My biggest concern now, is taking thin pieces of cardboard, and gluing them to thicker, formed pieces of cardboard, to make a larger, more complex form to be the top of the shell