Chuck
When I earned my Pvt/Cml/CFI, tailwheel endorsements didn't exist. I was grandfathered in. I basically taught myself to be as proficient as possible before giving instruction. Years later, I wonder how I did it compared to what I know now.
All an instructor needs is a tailwheel endorsement to meet FAA requirements for operation and instruction. The endorsement goes to his pilot's license. While that is not really a solid qualifier for giving tailwheel instruction, neither is being nosewheel qualified in a 206 a qualifier for backcountry instruction with DA and heavy load issues. The "student" should exercise due diligence in finding an instructor, while understanding caveat emptor.
The POH and FAA PTS descriptions of short and soft field operations only scratches the surface of what to do in the backcountry. Unfortunately, that is usually the extent of the run-of-the-mill flight instructor's knowledge and experience.