Is it OK to run a set without the picture tube?

[N2IXK]

Or just connect it to any CRT; color or B&W, and ground the aquadag coating of said tube to the chassis. That will dummy-load the high voltage circuit safely.

Just connecting the anode lead to a floating CRT will NOT provide a load on the HV. The return path for the HV is the beam current, drawn from the cathode of the CRT. If the CRT isn't plugged in, there will be no beam current, and no load is presented to the HV supply. The external dag coating provides the grounded side of the HV filter capacitance, not the return path for the HV.

That said, there is no real problem running a chassis without the CRT installed. Obviously, a series heater set will need the CRT heater pins jumped with an appropriate resistor so the rest of the tubes light up. Measurements of CRT electrode voltages may be a bit off, without the tube drawing any current.

Pulling the 1B3 is a good way to disable the HV and render the anode lead safe, but make sure that the 1B3 cap is well away from anything inside the HV cage to prevent arcing.