This is a big day for me. I've powered up the keyboard for the first time. I have not yet connected the pulse givers (dials) as the perspex pieces were not correct. I also have not been able to test all leds as the 2N3906 transistors I use are not in stock at Elfa. I do, however, suspect that using the transistors, at least in my config, is a waste, it seems the power is drawn from the controlling circuit, not trough the transistor.
The 7 leds that I've been able to connect work flawlessly, in both red and green modes. I've also (temporarily) connected the PCBs to the aluminium from Schaeffer. Some pics below.