Hey, cool. The contractors came through, and I can now steer wifi clients between access points on command. We don't yet have a "brain" program that will actually send the actual commands, but I figure... how hard can it be, right??
In other news, Android L and later are supposed to have improved background scanning so that when you kick them off your AP for steering purposes, they can join another AP very fast (because they've already been surveying the environment in the background). That seems true! My near-dead-with-bloat 2012 Nexus 7 with Android L (NEVER EVER DO THAT) transitions in tens of milliseconds without a glitch. The future of wifi might actually be bright.