So earlier at practice I experimented with flat feet coming off every wall. There was a very noticeable difference. I could surface with ease past the flags, without any DKs. In my first two years of swimming, I have used just the balls (and toes) of my feet in coming off the walls.
Flat feet (that is, both ball and heel) feels a little awkward right now, like any technique change, but I think I'm going to start adjusting to it for permanent use.
Thanks to Jim Thornton who suggested I make this a poll!