The program has been written and the logic for when to nudge the hour hand has been debugged with plenty of Serial.print(). It is missing the clock stuff, as I still need to find a clockchip in my stuff or buy one.

A simple circuit with a ULN2001 to drive a simple 4 coil stepper has been created, and yes, the motor moves as it is supposed to.

Didn't need the the "Stepper" library, I just drive the 4 pins. With only full steps, the program logic is trivial. Turned off when stationary.

Having some difficulty with the stepper choice, both mechanical and electrical. I have a good stepper but it is large and heavy, but it runs at 5V with 200 steps/revolution. I have a smaller stepper which is better, but has only 50 steps/revolution, which is too coarse. OK, so a simple large gear on the hands being driven by the stepper would do it. I only need 4:1 or better. The lighter stepper wants 24V - but that is for full power, I can drive it at anything 10V-24V, the torque is still more than enough to move the hands. Which means two power rails (5V and something >10V), either two walwarts or a stepdown converter

Whilst I use a normal Arduino for development work, I want it on a dedicated board at the end.

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I'll go with the heavy 5V motor, to get a "beta"-version constructed. Pro: No gears, simple 5V supply, Con: heavy/bulky behind clockface.