Further down the conversion road I decided to unplug the symbol nixie, that would not be used in a clock anyway. Plan was to try to unsolder its socket, but the dense pinout looks familiar. A quick check at the datasheet reveals that those pins are 2.54 mm apart (or 0.1" if you prefer). Moreover the ZM1001 has only 6 symbols + the anode, so a "modern" socket can be built out of few female headers on a breadboard or custom PCB.
Here's a possible layout (bottom view):
There are no overlapping (red) lines and, if the homebrew socket does not bring unused pins to the board, a simple veroboard can be used:
|Veroboard view of the homemade partial socket.|
|The tube sits well in the socket and has headroom so that pins are not stressed.|