The PCBs arrived a while ago, but I've been busy with other projects. Today I finally took the time to assemble it:
There isn't really much there. The Attiny24, a few pin headers, a grove connector, and the servo horns. I will probably move the grove connector on this side of the PCB, next to the servo pins — but mounted flat, soldered to SMD pads instead of holes. This way the back side of the PCB will be flat and the pins won't interfere with the servo horn. Here's an assembled leg:
So I think that mechanically I have it pretty much where I want to have it, the next step is software — first, PWM and I²C, and then the more advanced features, if they fit (I might need to switch to Attiny44 at some point).