Thanks, Phil. Yellow poplar is one of the most stable woods when properly dried, which is one big reason we used it for the Superceders. The trees tend to grow straight and clear, so the yield is good when sawing. In properties, poplar is slightly stronger and much tougher than POC. I think it is the best of the hardwoods, strong, stable, and heavy enough.
I have almost depleted my supply. The only shafts I'm interested in selling now are 70-75#, 32" length, and some 45-50# that are 29" length. Anyone interested can PM me. I only have a few odds and ends left except for these, most of which will be my personal lifetime supply!