Mine came out looking like lettuce rather than cabbage, but that's okay!
This was a fun project!
I actually started putting these together while the filters were still wet because I have no patience. It was a bit messy, but not too bad--like working with papier mache. Once I got a filter pinned on what would be the top of the cabbage, I turned it upside down on a drinking glass and started layering the rest of the filters on, pinning them at what would be the bottom and lower sides. I put one last filter over all the pins and just pressed that one in place--no pinning. I didn't do anything with the tops of the "leaves" at this point.
I let this all dry which only took a couple of hours. Once it was dry, I took off the that last, loose filter and ran an Elmer's Glue Dot Runner all around the edges and pressed it back in place. Then I flipped the cabbage up and used the glue dots to press in and hold all the "leaves" closer to the form rather than pinning, and kind of bent them out to look like the real thing. The glue dots worked great--no pins are showing! (Danni managed to do hers without the pins showing. I'm sure she might be able to give you some advice on how to do it. I had the glue dots and gave that a try.)