I used 28ga with mine. I just don't have the moxy to use 30ga as some have suggested. I think 24ga would be to large to fit in the chimney, could be wrong though.
I hope my build last for a while. I do rotate tanks with 4 Kayfuns and a Squape. Building and wicking the Fogger is not my favorite thing to do. I find it very temperamental. When you get it right, it's great...but if anything is a tad off, then problems ensue.