When assembling the 4 Wemos clocks I have built, I ran into a problem which made assembly a bit difficult, and which could be fixed with a modification to your PCBs. I thought I would mention it so you could consider this for future projects.
When installing the IN12s into the display board, I wanted the base of the tube to be close to the PCB so I had good illumination of by the RGB LEDs behind the tubes. This meant either installing low profile sockets, or directly soldering the tubes onto the board. In either case, you will need to ream out the PCB pin holes for the nixie tubes to get a fit. Unfortunately, this removes the plated through part of the pin hole, disconnecting the top and bottom layers of the pcb from each other. Since some of the tube connections are on the top of the pcb (directly under the tube), this means you will need to get a soldering iron under the tube to solder the pin on the top side, and also soldering the pins on the bottom side.
I suggest that you add an explicit via connecting the top and bottom layer next to each tube pin - especially for traces where the connection to the tube pin is routed on the top (tube side) layer; or where the top and bottom layers are connected through the pin plated through hole. This way, if you break the plated through hole by reaming, you still have a connection through the explicit via.
I've built loads of these myself, and have never had the problem that the tube pins don't fit in the holes. Either the latest batch of display boards has an error (holes too small) or the tubes have pins that have been desoldered from some equipment. Could you let me know which of these is the most reasonable explanation in your case?
It's not a big problem to have the boards made with larger holes, or even have pin receptacles for the IN-12s (although this will put the price up a bit).
Having said all that, it's not a bad idea to join the top and bottom layer in any case. Thanks for the suggestion!
The tube were listed as New-Old Stock. I didn't think they were pulls, but it is possible. Here are a couple of pictures of the pin end of tubes left over from that lot. They were a variety of date codes.
Add the same problem with my modular clock for nixie IN-8. The pin are stronger than IN-8a and if you push too far the tube, it gets cracked. Maybe a larger hole would be gret. I ended up buying and soldering connectors.
Yes, I see this problem also with the IN-2. I'm still thinking how to make it so that the tube stays physically supported but does not crack the base. I am wondering if spacers that go over some pins would help this. I don't really have a good answer right now...