I've tried it. It definitely works & speeds up my workflow.
What seems to work best is to sync & edit your left & right eyes together in FCP then send the timeline into Motion.
Consolidate your left & right eyes into separate groups in Motion, then apply the Dashwood plugin to an empty layer or a color solid and drop they left and right layers into the left & right image wells. Adjust, tweak, done.
Arnie
Post production is
not an afterthought!
http://www.arniepix.com/