Measuring how much a head was shaved?

Pondered this, and maybe I'm full of hooey- to my way of thinking you'd have to reference the cut against another machined surface, and the only semi-reliable one would be the rocker shaft saddles, which should be cut to a fairly standard dimension from the deck surface... So (if they're econo W2s with cast-in pedestals) would you be able to use the distance from the newly cut surface to the botton of the saddles of the shaft pedestals, compare to a set of uncut heads and come up with a close number? Of course this goes out the window if the W2s have separate rocker stands.
Crazy?