To perfectly center the drill in the template, I used a spring loaded self-centering drill bit, the kind carpenters use to drill pilot holes to install hinges.
You can see here how centered the holes are in the template.
Here’s the board after all 397 holes have been drilled
Next is cleanup of the holes, finish the edges and figure out how to store the pegs.
Then I’ll put a finish on this Curly Maple.