Ahh, cutting circles. You can cut sub road bed circles with a circular saw and smaller circles on a table saw.
If you encounter dexterity difficulty while cutting curved road bed with the circular saw there are even dished blades available for circular cutting with a circular saw.
Table saw small circle cutting is done with a table mounted pivot. It blew me away when an elderly deaf mute master carpenter showed me how to do this. He could not speak but was one of my best instructors.
I agree with John, The pair of top holes or even the diagonal side slots are a pain to use because you are applying uneven pressure and the plug, especially if thick, will jam. Just remove the mandrel. A vise helps. Also cutting half way from each side will give you a pull out handle.
The frequent point of difficulty with a hole saw is cost. You only want a sharp hole saw and the cost can be an issue. Plus, an assortment of them for on site use can get heavy & stolen. I have several dozen for wood and tile, Extremely helpful.
