It wasn't easy to find the right neon bulb for that project. They are mostly too small.
Those nice, big beehive lamps, that amateurs used in the 1920s, are not available on Ebay anymore.
There are bulbs with large electrodes, but they are not that bright because of the coating, they are more decorative.

I have two of those crater bulbs in the picture. This one was already broken, so I opened the base to check for the internal resistors. There are two inside, and they both have to go.
I want the tube to draw current through the bulb, and they would be just in the way - reducing contrast.
The tube itself will have enough internal resistance to prevent the current from running away.

This one is either from the 1930s or a more modern replica (resistors look younger), but it is so far the closest I can get to a 1920s type. Technically very comparable, though.