Do it yourself..
I re-finished my Sterba, not much science to it unless it has significant missing chunks. A bit of careful sanding (evenly) and a few coats of urethane. I also sprayed the backside flat black after the urethane. Balanced with a tube through the hub hole and set on some machete blades. Spray additional urethane on light blade. Cost all of $10.00, and looks like new.