I checked the balance roughly by putting a srew through the centre and seeing if one end dipped down. It seemed ok. Does it need to be measured more accurately than that.
Yes, if you're going to go to any trouble to check, then use something that will do the job with some accuracy. What size screw actually fit into a 10-6 prop's hole? That had to be one heck of a screw. ..... hmmmm?????