One problem with using inches, pints, and hectares is that federal agencies usually require metric measurement. As well, publications often direct metric for linear measurements. Another issue is that we are talking about pieces of objects, not complete dishes, teapots, and full-length boards. I dont see anything wrong with stating that "calculations based on the arc of a rim sherd suggests this 2.5 centimeter long fragment probably measured 9-inches when complete." In my experiece, federal and state agencies,  wanted distances measured in metric to satisfy reviewing agencies. Instead of beating your breasts and making "Custer's last stand" on this issue, why not find out what your SHPO thinks on this issue and then ask the lead agency directing your client to hire you what they want in your reports?

Ron May
Legacy 106, Inc.