Oh - one more. On those portholes, you are better off drilling before assembly, but you absolutely need zero rake drill bits and a good drill press. You need to clamp the sides securely on a wood block and to the drill press table. "Step-drills" are usually zero rake, and work well on work that is properly clamped.
You need zero rake drills for all holes bigger than #56. Difficult to buy, but you can dress regular drills with a Dremel cutoff disc and a magnifying glass. Drilling brass with ordinary twist drills varies from unsuccessful to dangerous.
