Recommend a good compass cutter?

It can be done if you go slowly with an xacto.

Either from a drawn circle, and I have an aluminum drafting triangle that has a number of small holes in it.

I used a compass (for drawing circles) and replaced the pencil bit with an xacto blade used for stencil cutting, they make small circles and the trick is to use light passes until it's all the way through instead of one heavy pass. I might try to design and machine an adaptor.

Another thing I am going to try is to buy a swivel knife, and see how small a circle I can trace out using a circle template.

I agree with Don, at that size a punch is needed.  I have a circle compass cutter and the smallest I can do it about 1/4 inch in diameter and even then that is tough to do.  A punch is the way to go.  They can be pricey, I have two sets of circle punches and they ran about $50 each but I get a ton of use out of them.  I use them on almost every build.  They are great for filling ejection pin marks, making small cockpit detail and for small masking needs just to name a few.

I think, to get circles that small, a punch set or hand punch might work much better.  Yeah, they will be more expensive, but a cutting compass will have a hard time at that kind of size.

For example, if I needed to draw a circle that small, I'd use a circle template rather than a regular compass.