You can build Bensen timber blades. We built six sets a number of years ago, and all flew fine, mostly with no adjustment to the trim tabs.
The difficult part is the scarfed joint on the plywood skins. This must be done well to be safe. We used the blades on our gyrogliders, and when
crow-hopping with power, but the power margin was not great with the VW engine. Probably would be fine with a 72 Mac and even better with a 90 Mac.
For better performance margins, we moved to extruded RotorHawks or Rotodynes.