True ride height
True ride height — the pair of measurements that describe a foil setup honestly. True foil height runs from the bottom of the board to the bottom of the fuselage; true rider height runs from the deck under your feet to the same point.
True ride height is two measurements, because one number cannot describe a foil setup honestly. True foil height runs from the bottom of the board to the bottom of the fuselage — where the foil actually sits, and what decides how high you can fly before the frontwing approaches the surface. True rider height runs from the deck under your feet to the same point — how far you are actually standing above the foil. Mast length describes neither reliably: there is no universal standard for where that measurement starts and stops, and it ignores the board thickness you are standing on.