It'd be neat if AfterEffects chromakey could handle the job. But I suspect it'd be as braindead as any other color selection tools I've seen. (Why can't they be vector-based, and less dependent on brightness?, he asked, rhetorically).
But maybe that histogram trick could be used - with a hand-corrected sample as a base... hmmm... but that'd get tedious with changing shots.
I can't tackle any projects for quite a while. I have a commitment to something that's going very slowly.