Les, if you do go the way of Dominos, then why not use the 10mm cutter plunging in 28mm on the widest setting, and make some home made dominos to fit. That would be stronger.
When I make big domies, just before I insert and glue up, I put them in an engineers vice and give it a ¼ turn to compress them a little. After putting some glue in the mortise and on the home made Domi, it swells back and you get a brilliant fit that is not starved of glue.
PS, when you compress them they expand in width a little, so you need to take that into account when you rip the stock. Make them a mill or so less in width.