Reddit reviews Dowel and Tenon Center Set 8-Piece, Two Dowel Centers for 1/4, 5/16, 3/8, and 1/2-Inch Holes, Two Tenon Centers for 3/16, 1/4, 5/16, and 3/8-Inch Pins
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You could always use dowels and use dowel markers for underside of table to mark where the dowels need to go.
These look cheap but should work if you go this route
https://www.amazon.com/Center-8-Piece-Centers-2-Inch-8-Inch/dp/B079HYZTTD?keywords=dowel+marker&qid=1536782311&s=Automotive&sr=1-9-catcorr&ref=mp_s_a_1_9