When I was playing around with the Carter on the '48, I went exploring to verify jet and orifice sizes.

I found that a set of micro drill bits did a good job in verifying jet sizes and - as a bonus - they were handy to clean out all of the 35+ years crud that managed to cling to passage walls.

A typical set:

https://www.impressart.com/540-20-pc...l-bit-set.html

These are standard English sizes - like Old Jeeps, not Chinese metric.