Agreed. Unnecessary for electrical, or thermal reasons, possibly damaged if the tube contact surface rides over them, and maybe structurally weakening. Imagine a heavy drop, upside down, and perhaps the cells smashing the centre out of the driver, or just cracking it.
Every via on a PCB adds to the manufacturing time, i.e. production cost. They are drilled one at a time using very expensive machinery, and drills that wear out. It is not good practice to use them unnecessarily. Simplistically put, if you can halve the number of vias in your design you can also halve the run time in the drill shop, get twice the throughput, or only need half as many machines.
The Q8 approach is tried and tested, and I think would be a better design to follow, for this important detail. Even then, early Q8s had problems with contact between the tube and the driver, mainly down to mechanical issues with PCB flatness, screws, finishing of the tube etc. which were later satisfactorily resolved. I’m simply pointing out that getting this seemingly minor detail right, turned out not to be quite as easy as it seemed.
There were many lessons learned during Q8 development and early production, hopefully there won’t be too many new ones (or old ones re-discovered) this time around.
Again, if that is a HASL finish (it certainly looks like it), and it is also intended to be used in production, then it would be incorrect for this application. It would wear through rapidly at the contact surface with the tube. It would also have to be RoHS compliant lead-free HASL.
The finish specified for the Q8 tube contact face should be used. It was carefully considered. Even then Thorfire did not follow the specified design, and what was delivered is not as good (too thin), but works well enough.
I also suggest double-checking the clearance of the components at the very edge, in the USB area. Are they definitely going to clear the metalwork inside the head ?
Otherwise it’s very interesting, I see lots of good ideas on this layout, and some experimental stuff too. Nice work.