Plugging holes in cabin top

What material should be used in plugging holes in the cabin top?
My DS1 came with several extra holes and poorly located fittings. These holes (1/8 to 3/8") need plugging. What material is best?
Gary Tabor (ratracer-at-rust.net)
My DS1 came with several extra holes and poorly located fittings. These holes (1/8 to 3/8") need plugging. What material is best?
Gary Tabor (ratracer-at-rust.net)