Thanks, all. As it happens, the project has evolved into something entirely different because the 2' wide doors were going to be a bit awkward to open. The new design is more of a barrister style bookcase, which should be easier to control for leverage points.
Still, the above advice is valuable. I've only used the domino to line up some joints on some frameless cabinets, and it worked very well for that.
Thanks,
Adam