http://www.robertkaufman.com/quiltin...scade/#color:1
Above is a link to the pattern. I don't think I would put #3 in the center. #2 fades too much into the background, and I wouldn't want to introduce the metallic in only one fabric, so I vote for #4. However here's another idea. If you have enough of the original fabric (#1) to use it in the center tumbler blocks, you could use #4 in the outer blocks that call for #1, and that would be a valid design choice.