Helping a friend restore a trestle table with sentimental value. Everything is going well but there are pieces missing from the bottom stretcher - one (two?) from each end. I would say they have to be wedges but the opening is: 1) horizontal, 2) not tapered, and 3) round on each end. I'm having a hard time visualizing what wedges that fit this space would look like.

Any thoughts?

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I have to figure out something to put there, even if it is not what used to be there, so any ideas are welcome.