Feign Thank you so much for the suggestion ... ive been using a bunch of razor blades stuck to a hollowed out magnet, by sliding the blads up to the beam scatter I can reduce it, but i love the threaded hole idea.... i have a piece of solid graphite ( quite black ) im going to try threading that now.

I have been theorizing exactly the scatter reduction technique you speak of on our white board, good to know with some confidence that multiple apertures is worth trying.