I measure my "true" draw length from the back of the bow, which is a real indicator of how far the bow is bending. So, my draw length is different between a thick, rigid handled bow and a thin, working handled bow. That's the most accurate and useful way to measure, IMO, especially for selfbows that don't typically have a pistol grip.
The A.M.O. standard for glass bows, however, is throat of grip + 1.25" (I think?). That sets a standard for the archer's draw, though, and not the bow's, which is easier for the masses...
