As expected, even though the variable capacitor was a massive Palstar model, a roller inductor has more friction, hence requires more torque.
When I spun it as fast as I could it drew just under 1 amp. That’s very reasonable. One BIG issue is that with “direct drive”, the set screws would unloosen – this is because the shafts of the stepper are stainless steel and there is rattle when you microstep.
Now I understand why Palstar and others use belt driven auto tuners with these large components!