TanyaL-you have the right idea. I was in Penn. at the MIL's house and she used flour and water for starch for my little girl's dresses. My mother boiled starch from a box named Argo and I used Niagara cold water starch for years.
My DD told me her husband wanted some of his clothes in the Air Force starched like you said, I guess inspections did that to them. They were criticized for any little wrinkle.
I guess people used whatever they had on hand. In the hippie days, people went back to using natural things for their homes and lifestyles. There were a couple books out for them that told them how to live the life of their ancestors. Back to basics was the name of the game. Today it looks like no one starches or irons shirts or blouses, they all look like they just came out of the washbasket, as my mother used to say.
Carol J.