I agree with Gerrit, your work is full of inventivity, it is really inspiring.
As rhino fan, I have already modify parts of your 3d PCB rhino keyboard and I thank you for all the work you have done. My goal is to make a 40% keyboard style using the 3D PCB principale and the nice design of the button you have made.
I have done my first keyboard prototype using the avalable material I had. I have used usual silicon cable 1.5mm² and find it very usefull. why do you prefer 0.07mm² tinned copper wire ? Have you tried other type of cable ?
I find insulated silicon cable usefull, you can put 2 wire in a unique channel or even cross cables. It is just like a double sided layer copper circuit. You can probably push the idea foreward and having more than two layers by getting as many cable you need into a deep chanel.
I have simplify your diamond channel profile. My printer is not as good as yours, you have done a lot of very fine detail that go way behond my printer capability. It push me to simplify the diamond channel by drawing a square shape of 1.7mm side length with a chamfer at top to avoid overhang print and get a super clean channel. It is working better than expected ! The cable is hold tight thank to the curves in the channel and yet really easy to insert.
I will post my keyboard here when finish.
Once again thank you for your great work, keep it going !