On Fri, 07 Feb 2014 08:21:10 -0600, Leon lcb11211@swbelldotnet
The through holes are exact width 5mm mortises, directly on top, 10mm
exact width, plunged about 3/16" .

Hmmm. I haven't used my 10mm Domino bit yet. Your 10mm bit slot looked
bigger than I thought it would have looked.

One other question. I haven't tried a through hole with the Domino
yet. Do you use a backer board when doing a Domino through hole?