Completely agree with you on those body measurements, they are pretty close to spot on for me too, however, my thumbs are in need of serious compression via G-clamps to get as wide as your ample digits
Therein lay the rudiments for a need for a standardised measurement (which was mentioned in the episode by means of a stick or staff with measurement marks noted for all trades to work to in case the measuree (?) passed away) If I made stuff to my rule of thumb it would probably let draughts in...along with rats and skinny thieves
I hope they do a follow up series, I am sure there is much more to learn.
Rob.