FWIW, I use the same needle for all my pinholes, from .15 mm up to about .55 mm so far. Since all the holes are smaller than the needle shaft, I just have to control how deeply I let the needle penetrate.

What I do is make a dimple that just penetrates, then sand off the dimple with a very fine whetstone (nice and flat, stays put, and I can use it with oil if I'm so inclined); measure (eyeball, if it's not close yet) and repeat as needed. I can usually make a hole within .001" (about .025 mm) of the desired size on the first or second try, and the resulting holes are perfectly round, burr free, and have a razor-thin edge. They aren't quite as clean as a Lenox Laser hole, but they're about $18 cheaper...

I use .001" thick brass shim stock, but you could just as easily use the thin aluminum from the side of a beverage can...