Does anyone else find it really hard to get wooden chests? It's harder than getting platinum chests, yet I need the leg wraps. >.<
If you use up all your moves, you can still complete the missions but your moves will no longer count towards the progress bar. So try using up all your moves on small 2 and 3 piece matches before trying to complete the missions and you should still stay within the wooden chest level.
I still haven't gotten the wraps either but I've been getting wooden chests with the above method.
One annoying thing I found is that we always good three points at the end of a round. I think that the amount of points should have to do with how well you did, e.g. if you for a crystal chest, you might get five points instead of three.
That's just my opinion though