Just to mention that I have some PCB's for either the ZM1350 or the
rev2 B7971 version.
Both pcb's allow for the closest possible spacing of the displays, and
of course you can spread them out as far as you want to also.
The B7971 tubes did not come back frm the board house wiht the holes
for the pin receptacles drilled to a useful size, but I can drill them
to any of the following sizes 1.5mm - 2.0mm - 2.5mm . If you wanted a
size in between then I could probably do that too. It helps with
assembly if you go to the high side with the holes, most B7971's have
bent pins and some misalignment can be catered for if you first fit
the receptacles to the pins and then slide the hole group of pins into
the boards holes before soldering them in place.
I am selling unpopulated boards with the relevant controller IC for £7.
Please get in touch if you would like some, they're gathering dust at