Question for any Fullmetal Alchemist lovers...?

Something has been in the back of my since the last arc of Fullmetal Alchemist began until now. They never really covered it, even at the end of the series (which almost made me ball because that was my favorite manga/anime EVER), but a specific detail about Father's nation-wide transmutation circle kind of came to me out of the blue. Izumi at some point explained to Ed and Al in a flashback about the basic components of a transmutation circle are a circle and runes. When the young Ed and Al ask her how she can transmute without drawing a circle says that clapping her hands together creates the circle and that she then becomes the rune. Did Father need sacrifices that saw the truth for his circle because they could act as the runes? Am I nerding too much over this lol?