I don't bother with legs, I only get back tendons.  Legs are hard to process, back tendons are easy.  A local processor saves the back tendons for me, and I usually get 4-5 pounds of dry back tendons each year.  I scrape them clean, including removing the membrane, then dry them on wax paper under a fan set on its lowest setting.  The tendons are dry in about 6 hours.  I then comb them on a home-made sinew comb made of pine and finishing nails for storage.  If I didn't comb, I'd need contractor garbage bags to store all of the back tendons, I end up with so many.