All

Thanks for the myriad ideas.

I cut my sample from a scrap of 2 X 4 and the resultant piece is 2-7/8” across -
about the right size for my final piece.

https://www.flickr.com/photos/ruby1638/32819574531/in/dateposted-public/

The pieces are just inconsistent enough in size that you can see that when the
outside surfaces are lined up, the centers don’t meet.  The three things that
seem to make the most sense are 1) make them as consistent as possible, 2) cut
the points off and put a small (1/4”?) dowel up the middle so they want to only
go in so far, and 2) Tom Conroys sage advice: