For accurate measurement of pitch, I clamp the flybar paddle horizontally on a piece of wood extending out from my vise. Cut off a broken blade close to the rotor hub and epoxy a 1/8" plywood platform to the end. Use this to hold a pocket level (yellow plastic, Home Depot, about 5" long). This gives you a good zero point. You can then cut a wedge of any angle you want to measure from plywood. Put this under the level to measure any angle. Seems like a lot of trouble but very accurate.