I have not used the pinking blade or the Omni Arc, but have used the wavy blade and you really need to be careful not to nic your ruler. I'll see if I can find anything else out there that might help you.
Did you notice that it says the lines are in 1" increments, so you would need to figure that into your circle as well?
I would be tempted to find a plate around the house that measures 7 ¼ "diameter and use it for the template to cute around. Just measured one here but it is 7½ " .... any flower pot etc. would work.
Last edited by thimblebug6000; 08-27-2016 at 01:13 PM.