I had no idea how much of a hassle this would be. I figured I'd just buy some garnet shellac, slap it on, and life would be good. Not so much.
The garnet shellac wasn't brown or dark enough. It actually looked very similar to the orange/amber shellac I had tried out in the summer. It added beautiful depth and color to the wood, but it wasn't what I was looking for. So then I bought all kinds of little sample packages of Varathane stain. Sample packs like that are God's gift to DIYers. After much sampling, I've finally decided on "golden mahogany". The absoloutely terrible photo below shows all of my attempts at finding the right color combination. Remind me not to take pictures before the sun comes up and/or I've had some coffee. The top of the right-hand board is the garnet shellac, with the amber shellac beneath it. I imagined garnet as a deep reddish hue, but it's very orang-y. More red-orange than red-brown.
Because our woodwork is pine, it's kind of difficult to stain without it turning out blotchy. Based on some recommendations, I decided to seal the wood first using a 1 lb cut of clear, dewaxed shellac (Zinnser SealCoat, thinned). The stain goes over that, then I coat it all with a coat of garnet shellac to bring out the red tones. And then a few coats of clear shellac over that for protection. Is that complicated enough? The resulting color just about perfectly matches the existing woodwork upstairs, which is what I am aiming for. I'll take a picture when the room has brightened up so that the flash doesn't wash it out.