Fine Tuning a 360 Magnum with a Brawler "Double Pumper"

Also are there any recommended drill bit sets I get for holes in thousandths? I can’t find any that aren’t metric or fractions
I have this one for the small sizes. Shows number and measured size for each from 1-60. I’d also recommend getting a number zero or number one center drill to start the holes so the drill doesn’t wander and drill straight without breaking. Just need to use the center drill to put a dimple in the brass that the drill can use as a guide to get started. There can be a trick to drilling small holes. You need to be patient and pet drill clearing the flute often.

Irwin Tools IRWIN Drill Bit Set, 60-Piece (80181) https://a.co/d/bfv0OuF