No Shim Needed
Such a cool idea to literally frame your small scale paper art! Two items of note:
1. Do not try to cut them all at once nested, the center frames will NOT cut. Cut each frame individually for best results. I have a Sizzix Big Shot Plus and no matter how I angled them or shimmed them, even using a metal detail shim, the three dies in the center wouldn't cut through on all sides! I had to use a craft knife to cut them apart so I didn't waste the effort!
2. I discovered while trying these myriad cutting sandwiches, that when shimmed, the wood grain lines actually cut through instead of just embossing.
Once I figured it all out, I was quite pleased and had plenty of "wood" frames to embellish future creations!
P.S. The 2nd smallest die is standard ATC sized! Yes, I have some showing this in my gallery!