Having an area instead of a single objective makes gaming quite a bit easier. Since there exists transparent material, why not 3D print these markers?

I added multiple versions: Small and Large for 3" radius and 40mm central +3". There are two parts (Large_1, Large_2 or Small_1 and Small_2) for the different colours. If you want to number them, you can use _Inner_Cutout instead of the normal _Inner, and add both of the number files, too.