Hi Harry,
My Craftsman Pro router has a poor sub plate design, ie., the small opening & you have to use Sears guides. (Which is why I love OP's plates, adversity

). However, as you very well know, the Makita's have a decent sized hole even in the sub plate. It's usually the sub plate that screws things up for routers.
Now, for the metric system. It's as I've said before, I don't know it but, always willing to learn it. Rather people truly realize it or not but, the U.S. is slowly changing over to metric. It's just a gradual change.
Just my thoughts.
