I am back again in the forum and would like to report what happened so far: Yesterday I took the Model01 out of its box again and started looking into things more seriously. I tried two or three firmware forks and flashed them onto the keyboard which was very easy, by the way.
Unfortunately none of them seemed to work well enough for me. I also found that I have to learn more about the Arduino C syntax. It seems to have some conventions I am not used to, and before trying more or different tweaks, I definitely need to have a better grasp. I actually have not used the graphical Arduino environment, but got along well with a text editor. The firmware file is well documented, and many things are easy enough to understand.
The other thing, of course, is really the big question: the keyboard has relatively few keys. Where do I put all the characters so it makes good sense for typing effectively? You definitely need all the layers available. This to me seems to be the hardest thing. I need a good plan and lots of correct key definitions (downloaded them already).
I am in exactly the same situation as Christopher who started this thread, and I, too, will probably need quite a few trials and errors. So far, the Model01 not of much use for me, although a very good piece of hardware. The solutions for German layout keyboards I have seen here, are mostly based on other approaches like Neo and the like. But since a new keyboard like the Model01 is always something you have to get used to anyway, I do not want to learn two things at a time and rather prefer to stick to QWERTZ.
I have always been interested in ergonomic keyboards, and since three years I have been using the Truly Ergonomic Keyboard which is very solid and well working and a pleasure to type on. It has a couple keys more than the Model01 and an interesting mechanism to switch between layouts by DIP switches. You also can switch to German layout, of course. But you also can create a completely custom layout for yourself with a web editor and flash that one to the keyboard.
When I learned about the Model01 and saw the pictures of the prototypes, I immediately thought that I would be interested in the project and ordered my Model01. It turns out now that this one here is more challenging for the end-users from outside the English-speaking world, and I think that there should really be something useable out of the box for them, too, if this keyboard should reach a market beyond the people who do not care about doing something themselves to make it work, and who have at least some basic knowledge of how to write a little bit of code.
I am taking it as a challenge and as an opportunity to learn something new. I think I will try and write my own firmware from scratch, and this will be rather a project for the summer, because you cannot do this with an occasional spare hour here and there. It will be my own personal Summer of Code…
I will come back and tell how it went when I will have a working firmware and share it if someone is interested.