You can get a dave platt spinner/backplate for $55 that is a resin dome and an aluminum backplate. Email him at
http://www.daveplattmodels.com/
The one for the 68" dave platt ME-109 is the exact right fit for this CMP ME-109
If, for some reason, you muck up the resin dome, you can get that replaced for only $30 without having to buy a new backplate.