Review on 📏 Accurate Measurements Made Easy: Introducing the TIPU Tipu Bevel Gauge by Draek Villareal

I suppose you should use this to center the knife in the middle of the groove and try to line up the knife blade bevel with the side. Then move the gauge perpendicular to the knife and see if the other side matches. Here you shouldn't just stick the knife in the slot and see if it fits. The problem is that when the grinding width is only about a millimeter, a bezel is difficult to grip with a sharp blade. You have to pull out a magnifying glass and have very strong hands. I can't confirm the accuracy of the angles because it was just hard to use.