[click through for larger pic and additional images]
So, once it was all done, I think I ended up using 10 packets of chestnut, two of crimson, and four of brown (14 pounds of fabric in the two covers). The result was exactly what I wanted -- warm chocolatey brown, pretty dang overdyed, but still unsaturated enough to have those gradations in the color that give it the natural hand-dyed look.
(Also, the iPhone camera is particularly skilled at showing how I need to wash my floor. It's not that obviously dusty in real life, I swear!)
The couch cushion covers are still in need of several more dye baths. Getting to about the saturation I want, but I think they're too far toward rust. Once they dry, I'll see where they're at and what they need next.