RE: Objective Testing / Measurements.
I have feet that measure to size 11.5 (US). I have shoes ranging in size from 11 to 13.
You have to try them on to know if they fit. Same with a board. To be sure, you have to ride it to see if sinks or floats, or if it works the way the promotions say.
It's not a perfect world.
I can see why Starboard came up with the "virtual volume" for their boards a while back, but common sense finally won out when the feedback from the end users prevailed.