Peter, agreed on your points about the tiller head. I think 2 years would be reasonable for everyone to adapt.
For A/16. instead of saying “shall be approximately perpendicular…” say “shall be 90 degrees, +- 2 degrees. Others can weigh in on what the tolerance should be. I don’t know if a 4 degree range is too much or too little. I think it should be pretty easy to build within that range and should fit existing hulls.
Steve